CVE-2026-89540

{"dataType": "CVE_RECORD", "dataVersion": "5.2", "cveMetadata": {"cveId": "CVE-2026-89540", "assignerOrgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "state": "PUBLISHED", "assignerShortName": "Linux", "dateReserved": "2026-09-11T19:38:34.721Z", "datePublished": "2026-09-11T19:44:17.440Z", "dateUpdated": "2026-10-19T08:48:31.930Z"}, "containers": {"cna": {"providerMetadata": {"orgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "shortName": "Linux", "dateUpdated": "2026-10-19T08:48:31.930Z"}, "descriptions": [{"lang": "en", "value": "In the Linux kernel, the following vulnerability has been resolved:\n\nsunrpc: init gssp_lock before publishing proc entry\n\ncreate_use_gss_proxy_proc_entry() publishes /proc/net/rpc/use-gss-proxy\nvia proc_create_data() before init_gssp_clnt() runs mutex_init() on\nsn->gssp_lock. Once the dentry is linked under proc_subdir_lock it is\nimmediately reachable from userspace, so a write that lands in the\nwindow drives set_gssp_clnt() into mutex_lock() on a zero-initialized\nstruct mutex.\n\n create_use_gss_proxy_proc_entry(net)\n proc_create_data(\"use-gss-proxy\", ...) /* dentry live */\n init_gssp_clnt(sn)\n mutex_init(&sn->gssp_lock) /* too late */\n\n write_gssp()\n set_gssp_clnt(net)\n mutex_lock(&sn->gssp_lock) /* uninitialized */\n gssp_rpc_create(...)\n sn->gssp_clnt = clnt\n mutex_unlock(&sn->gssp_lock)\n\nThe window spans only the two statements between proc_create_data()\nreturning and init_gssp_clnt(), so a writer reaches it only if the\nregistering thread is preempted there while another task is already\nopening the freshly published file. register_pernet_subsys() runs in\npreemptible context under pernet_ops_rwsem, so that preemption is\npossible, and the window widens on auth_rpcgss module load, when the\nproc entry is created for every live net namespace whose tasks are\nalready running. A writer that wins the race locks a zero-filled\nstruct mutex. On CONFIG_DEBUG_MUTEXES the missing magic value trips a\n\"lock used without init\" splat; on a production kernel the fast path\nacquires the lock via CMPXCHG(owner, 0, current). In the latter case\na second writer that arrives before init_gssp_clnt() re-zeroes owner\ncan enter set_gssp_clnt() concurrently, shut down the first writer's\nclnt while it is still in use, and leak the loser's clnt.\n\nFix by initializing sn->gssp_lock in sunrpc_init_net() so its lifetime\nmatches the sunrpc_net it lives in. sn->gssp_clnt is already NULL from\nthe kzalloc that backs net_generic storage, so the lazy helper is no\nlonger needed; drop init_gssp_clnt(), its prototype, and the call from\ncreate_use_gss_proxy_proc_entry(). sunrpc.ko is a build-time\ndependency of auth_rpcgss.ko, so sunrpc_init_net() has always run on\nevery netns before any auth_gss pernet init can publish the proc\nentry."}], "metrics": [{"cvssV3_1": {"version": "3.1", "vectorString": "CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H", "baseScore": 7.8, "baseSeverity": "HIGH"}, "scenarios": [{"lang": "en", "value": "AV:L - The bug is reached only by write(2) to /proc/net/rpc/use-gss-proxy (write_gssp \u2192 set_gssp_clnt \u2192 mutex_lock(&sn->gssp_lock)); remote NFS/RPC peers never hit that procfs path.\nAC:L - The attacker fully controls writer threads that hammer the proc file, and on auth_rpcgss module load register_pernet_subsys() publishes it for every live netns whose tasks are already running; preemption between proc_create_data() and mutex_init() is possible in that preemptible pernet context, so the race is attacker-driven.\nPR:L - The 0600 use-gss-proxy entry inherits /proc/net ownership from proc_net_ns_init()'s make_kuid(net->user_ns, 0), so an unprivileged user who unshares user+net namespaces owns the file; write_gssp() has no capable() check.\nUI:N - The attacker creates the namespace and writes \"1\" to the proc file from their own tasks; no victim must mount a filesystem, open a file, or otherwise cooperate.\nS:U - Uninitialized-mutex use and concurrent rpc_clnt teardown corrupt host kernel memory inside the same kernel security authority; this is not a VM escape, IOMMU bypass, or other cross-boundary impact.\nC:H - A writer that wins the race locks a zeroed mutex; mutex_init() can then re-zero owner so a second writer enters set_gssp_clnt() concurrently and rpc_shutdown_client()s a live rpc_clnt, a use-after-free that per kernel guidance yields an arbitrary read primitive.\nI:H - Concurrent set_gssp_clnt() can shut down an in-use rpc_clnt (UAF) while mutex_init() of a held lock corrupts mutex wait-list state, giving heap/lock-structure writes exploitable for control-flow hijack rather than a pure crash.\nA:H - CONFIG_DEBUG_MUTEXES treats the uninitialized lock as a lock-used-without-init splat/oops, and on production kernels the rpc_clnt UAF and corrupted mutex wait lists cause a kernel oops or panic."}]}], "affected": [{"product": "Linux", "vendor": "Linux", "defaultStatus": "unaffected", "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git", "programFiles": ["net/sunrpc/auth_gss/gss_rpc_upcall.c", "net/sunrpc/auth_gss/gss_rpc_upcall.h", "net/sunrpc/auth_gss/svcauth_gss.c", "net/sunrpc/sunrpc_syms.c"], "versions": [{"version": "030d794bf49855f5e2a9e8dfbfad34211d1eb08b", "lessThan": "159a4fab7170badd6c4a553aef81cac079d6f4ee", "status": "affected", "versionType": "git"}, {"version": "030d794bf49855f5e2a9e8dfbfad34211d1eb08b", "lessThan": "b3526ae3351968f6726bcbe25d8d09973ad79109", "status": "affected", "versionType": "git"}, {"version": "030d794bf49855f5e2a9e8dfbfad34211d1eb08b", "lessThan": "7f5bcdc8da15077ebe846c2756a5a17741021410", "status": "affected", "versionType": "git"}, {"version": "030d794bf49855f5e2a9e8dfbfad34211d1eb08b", "lessThan": "89c8e0733e8c46b7973503f15b1b31a8587d8030", "status": "affected", "versionType": "git"}, {"version": "030d794bf49855f5e2a9e8dfbfad34211d1eb08b", "lessThan": "f15b87521168c2a92cb1931f532cba422f856f01", "status": "affected", "versionType": "git"}, {"version": "030d794bf49855f5e2a9e8dfbfad34211d1eb08b", "lessThan": "edeefb111d6181a4aa278f415b005efe284b9489", "status": "affected", "versionType": "git"}, {"version": "030d794bf49855f5e2a9e8dfbfad34211d1eb08b", "lessThan": "3f019571928b269feebcff59926ec13294215e0e", "status": "affected", "versionType": "git"}, {"version": "030d794bf49855f5e2a9e8dfbfad34211d1eb08b", "lessThan": "5ce1ed6159731a41fdd0b03eedbed4e147036a5a", "status": "affected", "versionType": "git"}]}, {"product": "Linux", "vendor": "Linux", "defaultStatus": "affected", "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git", "programFiles": ["net/sunrpc/auth_gss/gss_rpc_upcall.c", "net/sunrpc/auth_gss/gss_rpc_upcall.h", "net/sunrpc/auth_gss/svcauth_gss.c", "net/sunrpc/sunrpc_syms.c"], "versions": [{"version": "3.10", "status": "affected"}, {"version": "0", "lessThan": "3.10", "status": "unaffected", "versionType": "semver"}, {"version": "5.10.270", "lessThanOrEqual": "5.10.*", "status": "unaffected", "versionType": "semver"}, {"version": "5.15.221", "lessThanOrEqual": "5.15.*", "status": "unaffected", "versionType": "semver"}, {"version": "6.1.188", "lessThanOrEqual": "6.1.*", "status": "unaffected", "versionType": "semver"}, {"version": "6.6.157", "lessThanOrEqual": "6.6.*", "status": "unaffected", "versionType": "semver"}, {"version": "6.12.109", "lessThanOrEqual": "6.12.*", "status": "unaffected", "versionType": "semver"}, {"version": "6.18.50", "lessThanOrEqual": "6.18.*", "status": "unaffected", "versionType": "semver"}, {"version": "7.2.4", "lessThanOrEqual": "7.2.*", "status": "unaffected", "versionType": "semver"}, {"version": "7.3", "lessThanOrEqual": "*", "status": "unaffected", "versionType": "original_commit_for_fix"}]}], "cpeApplicability": [{"nodes": [{"operator": "OR", "negate": false, "cpeMatch": [{"vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "3.10", "versionEndExcluding": "5.10.270"}, {"vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "3.10", "versionEndExcluding": "5.15.221"}, {"vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "3.10", "versionEndExcluding": "6.1.188"}, {"vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "3.10", "versionEndExcluding": "6.6.157"}, {"vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "3.10", "versionEndExcluding": "6.12.109"}, {"vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "3.10", "versionEndExcluding": "6.18.50"}, {"vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "3.10", "versionEndExcluding": "7.2.4"}, {"vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "3.10", "versionEndExcluding": "7.3"}]}]}], "references": [{"url": "https://git.kernel.org/stable/c/159a4fab7170badd6c4a553aef81cac079d6f4ee"}, {"url": "https://git.kernel.org/stable/c/b3526ae3351968f6726bcbe25d8d09973ad79109"}, {"url": "https://git.kernel.org/stable/c/7f5bcdc8da15077ebe846c2756a5a17741021410"}, {"url": "https://git.kernel.org/stable/c/89c8e0733e8c46b7973503f15b1b31a8587d8030"}, {"url": "https://git.kernel.org/stable/c/f15b87521168c2a92cb1931f532cba422f856f01"}, {"url": "https://git.kernel.org/stable/c/edeefb111d6181a4aa278f415b005efe284b9489"}, {"url": "https://git.kernel.org/stable/c/3f019571928b269feebcff59926ec13294215e0e"}, {"url": "https://git.kernel.org/stable/c/5ce1ed6159731a41fdd0b03eedbed4e147036a5a"}], "title": "sunrpc: init gssp_lock before publishing proc entry", "x_generator": {"engine": "bippy-1.2.0"}}, "adp": [{"metrics": [{"other": {"type": "ssvc", "content": {"id": "CVE-2026-89540", "role": "CISA Coordinator", "options": [{"Exploitation": "none"}, {"Automatable": "no"}, {"Technical Impact": "total"}], "version": "2.0.3", "timestamp": "2026-10-16T19:23:23.496498Z"}}}], "title": "CISA ADP Vulnrichment", "providerMetadata": {"orgId": "134c704f-9b21-4f2e-91b3-4a467353bcc0", "shortName": "CISA-ADP", "dateUpdated": "2026-10-16T19:26:42.049Z"}}]}}

{"dataType": "CVE_RECORD", "containers": {"adp": [{"title": "CISA ADP Vulnrichment", "metrics": [{"other": {"type": "ssvc", "content": {"id": "CVE-2026-89540", "role": "CISA Coordinator", "options": [{"Exploitation": "none"}, {"Automatable": "no"}, {"Technical Impact": "total"}], "version": "2.0.3", "timestamp": "2026-10-16T19:23:23.496498Z"}}}], "providerMetadata": {"orgId": "134c704f-9b21-4f2e-91b3-4a467353bcc0", "shortName": "CISA-ADP", "dateUpdated": "2026-10-16T19:23:24.509Z"}}], "cna": {"title": "sunrpc: init gssp_lock before publishing proc entry", "metrics": [{"cvssV3_1": {"version": "3.1", "baseScore": 7.8, "baseSeverity": "HIGH", "vectorString": "CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H"}, "scenarios": [{"lang": "en", "value": "AV:L - The bug is reached only by write(2) to /proc/net/rpc/use-gss-proxy (write_gssp \u2192 set_gssp_clnt \u2192 mutex_lock(&sn->gssp_lock)); remote NFS/RPC peers never hit that procfs path.\nAC:L - The attacker fully controls writer threads that hammer the proc file, and on auth_rpcgss module load register_pernet_subsys() publishes it for every live netns whose tasks are already running; preemption between proc_create_data() and mutex_init() is possible in that preemptible pernet context, so the race is attacker-driven.\nPR:L - The 0600 use-gss-proxy entry inherits /proc/net ownership from proc_net_ns_init()'s make_kuid(net->user_ns, 0), so an unprivileged user who unshares user+net namespaces owns the file; write_gssp() has no capable() check.\nUI:N - The attacker creates the namespace and writes \"1\" to the proc file from their own tasks; no victim must mount a filesystem, open a file, or otherwise cooperate.\nS:U - Uninitialized-mutex use and concurrent rpc_clnt teardown corrupt host kernel memory inside the same kernel security authority; this is not a VM escape, IOMMU bypass, or other cross-boundary impact.\nC:H - A writer that wins the race locks a zeroed mutex; mutex_init() can then re-zero owner so a second writer enters set_gssp_clnt() concurrently and rpc_shutdown_client()s a live rpc_clnt, a use-after-free that per kernel guidance yields an arbitrary read primitive.\nI:H - Concurrent set_gssp_clnt() can shut down an in-use rpc_clnt (UAF) while mutex_init() of a held lock corrupts mutex wait-list state, giving heap/lock-structure writes exploitable for control-flow hijack rather than a pure crash.\nA:H - CONFIG_DEBUG_MUTEXES treats the uninitialized lock as a lock-used-without-init splat/oops, and on production kernels the rpc_clnt UAF and corrupted mutex wait lists cause a kernel oops or panic."}]}], "affected": [{"repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git", "vendor": "Linux", "product": "Linux", "versions": [{"status": "affected", "version": "030d794bf49855f5e2a9e8dfbfad34211d1eb08b", "lessThan": "159a4fab7170badd6c4a553aef81cac079d6f4ee", "versionType": "git"}, {"status": "affected", "version": "030d794bf49855f5e2a9e8dfbfad34211d1eb08b", "lessThan": "b3526ae3351968f6726bcbe25d8d09973ad79109", "versionType": "git"}, {"status": "affected", "version": "030d794bf49855f5e2a9e8dfbfad34211d1eb08b", "lessThan": "7f5bcdc8da15077ebe846c2756a5a17741021410", "versionType": "git"}, {"status": "affected", "version": "030d794bf49855f5e2a9e8dfbfad34211d1eb08b", "lessThan": "89c8e0733e8c46b7973503f15b1b31a8587d8030", "versionType": "git"}, {"status": "affected", "version": "030d794bf49855f5e2a9e8dfbfad34211d1eb08b", "lessThan": "f15b87521168c2a92cb1931f532cba422f856f01", "versionType": "git"}, {"status": "affected", "version": "030d794bf49855f5e2a9e8dfbfad34211d1eb08b", "lessThan": "edeefb111d6181a4aa278f415b005efe284b9489", "versionType": "git"}, {"status": "affected", "version": "030d794bf49855f5e2a9e8dfbfad34211d1eb08b", "lessThan": "3f019571928b269feebcff59926ec13294215e0e", "versionType": "git"}, {"status": "affected", "version": "030d794bf49855f5e2a9e8dfbfad34211d1eb08b", "lessThan": "5ce1ed6159731a41fdd0b03eedbed4e147036a5a", "versionType": "git"}], "programFiles": ["net/sunrpc/auth_gss/gss_rpc_upcall.c", "net/sunrpc/auth_gss/gss_rpc_upcall.h", "net/sunrpc/auth_gss/svcauth_gss.c", "net/sunrpc/sunrpc_syms.c"], "defaultStatus": "unaffected"}, {"repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git", "vendor": "Linux", "product": "Linux", "versions": [{"status": "affected", "version": "3.10"}, {"status": "unaffected", "version": "0", "lessThan": "3.10", "versionType": "semver"}, {"status": "unaffected", "version": "5.10.270", "versionType": "semver", "lessThanOrEqual": "5.10.*"}, {"status": "unaffected", "version": "5.15.221", "versionType": "semver", "lessThanOrEqual": "5.15.*"}, {"status": "unaffected", "version": "6.1.188", "versionType": "semver", "lessThanOrEqual": "6.1.*"}, {"status": "unaffected", "version": "6.6.157", "versionType": "semver", "lessThanOrEqual": "6.6.*"}, {"status": "unaffected", "version": "6.12.109", "versionType": "semver", "lessThanOrEqual": "6.12.*"}, {"status": "unaffected", "version": "6.18.50", "versionType": "semver", "lessThanOrEqual": "6.18.*"}, {"status": "unaffected", "version": "7.2.4", "versionType": "semver", "lessThanOrEqual": "7.2.*"}, {"status": "unaffected", "version": "7.3", "versionType": "original_commit_for_fix", "lessThanOrEqual": "*"}], "programFiles": ["net/sunrpc/auth_gss/gss_rpc_upcall.c", "net/sunrpc/auth_gss/gss_rpc_upcall.h", "net/sunrpc/auth_gss/svcauth_gss.c", "net/sunrpc/sunrpc_syms.c"], "defaultStatus": "affected"}], "references": [{"url": "https://git.kernel.org/stable/c/159a4fab7170badd6c4a553aef81cac079d6f4ee"}, {"url": "https://git.kernel.org/stable/c/b3526ae3351968f6726bcbe25d8d09973ad79109"}, {"url": "https://git.kernel.org/stable/c/7f5bcdc8da15077ebe846c2756a5a17741021410"}, {"url": "https://git.kernel.org/stable/c/89c8e0733e8c46b7973503f15b1b31a8587d8030"}, {"url": "https://git.kernel.org/stable/c/f15b87521168c2a92cb1931f532cba422f856f01"}, {"url": "https://git.kernel.org/stable/c/edeefb111d6181a4aa278f415b005efe284b9489"}, {"url": "https://git.kernel.org/stable/c/3f019571928b269feebcff59926ec13294215e0e"}, {"url": "https://git.kernel.org/stable/c/5ce1ed6159731a41fdd0b03eedbed4e147036a5a"}], "x_generator": {"engine": "bippy-1.2.0"}, "descriptions": [{"lang": "en", "value": "In the Linux kernel, the following vulnerability has been resolved:\n\nsunrpc: init gssp_lock before publishing proc entry\n\ncreate_use_gss_proxy_proc_entry() publishes /proc/net/rpc/use-gss-proxy\nvia proc_create_data() before init_gssp_clnt() runs mutex_init() on\nsn->gssp_lock. Once the dentry is linked under proc_subdir_lock it is\nimmediately reachable from userspace, so a write that lands in the\nwindow drives set_gssp_clnt() into mutex_lock() on a zero-initialized\nstruct mutex.\n\n create_use_gss_proxy_proc_entry(net)\n proc_create_data(\"use-gss-proxy\", ...) /* dentry live */\n init_gssp_clnt(sn)\n mutex_init(&sn->gssp_lock) /* too late */\n\n write_gssp()\n set_gssp_clnt(net)\n mutex_lock(&sn->gssp_lock) /* uninitialized */\n gssp_rpc_create(...)\n sn->gssp_clnt = clnt\n mutex_unlock(&sn->gssp_lock)\n\nThe window spans only the two statements between proc_create_data()\nreturning and init_gssp_clnt(), so a writer reaches it only if the\nregistering thread is preempted there while another task is already\nopening the freshly published file. register_pernet_subsys() runs in\npreemptible context under pernet_ops_rwsem, so that preemption is\npossible, and the window widens on auth_rpcgss module load, when the\nproc entry is created for every live net namespace whose tasks are\nalready running. A writer that wins the race locks a zero-filled\nstruct mutex. On CONFIG_DEBUG_MUTEXES the missing magic value trips a\n\"lock used without init\" splat; on a production kernel the fast path\nacquires the lock via CMPXCHG(owner, 0, current). In the latter case\na second writer that arrives before init_gssp_clnt() re-zeroes owner\ncan enter set_gssp_clnt() concurrently, shut down the first writer's\nclnt while it is still in use, and leak the loser's clnt.\n\nFix by initializing sn->gssp_lock in sunrpc_init_net() so its lifetime\nmatches the sunrpc_net it lives in. sn->gssp_clnt is already NULL from\nthe kzalloc that backs net_generic storage, so the lazy helper is no\nlonger needed; drop init_gssp_clnt(), its prototype, and the call from\ncreate_use_gss_proxy_proc_entry(). sunrpc.ko is a build-time\ndependency of auth_rpcgss.ko, so sunrpc_init_net() has always run on\nevery netns before any auth_gss pernet init can publish the proc\nentry."}], "cpeApplicability": [{"nodes": [{"negate": false, "cpeMatch": [{"criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "vulnerable": true, "versionEndExcluding": "5.10.270", "versionStartIncluding": "3.10"}, {"criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "vulnerable": true, "versionEndExcluding": "5.15.221", "versionStartIncluding": "3.10"}, {"criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "vulnerable": true, "versionEndExcluding": "6.1.188", "versionStartIncluding": "3.10"}, {"criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "vulnerable": true, "versionEndExcluding": "6.6.157", "versionStartIncluding": "3.10"}, {"criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "vulnerable": true, "versionEndExcluding": "6.12.109", "versionStartIncluding": "3.10"}, {"criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "vulnerable": true, "versionEndExcluding": "6.18.50", "versionStartIncluding": "3.10"}, {"criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "vulnerable": true, "versionEndExcluding": "7.2.4", "versionStartIncluding": "3.10"}, {"criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "vulnerable": true, "versionEndExcluding": "7.3", "versionStartIncluding": "3.10"}], "operator": "OR"}]}], "providerMetadata": {"orgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "shortName": "Linux", "dateUpdated": "2026-10-19T08:48:31.930Z"}}}, "cveMetadata": {"cveId": "CVE-2026-89540", "state": "PUBLISHED", "dateUpdated": "2026-10-19T08:48:31.930Z", "dateReserved": "2026-09-11T19:38:34.721Z", "assignerOrgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "datePublished": "2026-09-11T19:44:17.440Z", "assignerShortName": "Linux"}, "dataVersion": "5.2"}

{"affected": [{"affectedData": [{"defaultStatus": "unaffected", "product": "Linux", "programFiles": ["net/sunrpc/auth_gss/gss_rpc_upcall.c", "net/sunrpc/auth_gss/gss_rpc_upcall.h", "net/sunrpc/auth_gss/svcauth_gss.c", "net/sunrpc/sunrpc_syms.c"], "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git", "vendor": "Linux", "versions": [{"lessThan": "159a4fab7170badd6c4a553aef81cac079d6f4ee", "status": "affected", "version": "030d794bf49855f5e2a9e8dfbfad34211d1eb08b", "versionType": "git"}, {"lessThan": "b3526ae3351968f6726bcbe25d8d09973ad79109", "status": "affected", "version": "030d794bf49855f5e2a9e8dfbfad34211d1eb08b", "versionType": "git"}, {"lessThan": "7f5bcdc8da15077ebe846c2756a5a17741021410", "status": "affected", "version": "030d794bf49855f5e2a9e8dfbfad34211d1eb08b", "versionType": "git"}, {"lessThan": "89c8e0733e8c46b7973503f15b1b31a8587d8030", "status": "affected", "version": "030d794bf49855f5e2a9e8dfbfad34211d1eb08b", "versionType": "git"}, {"lessThan": "f15b87521168c2a92cb1931f532cba422f856f01", "status": "affected", "version": "030d794bf49855f5e2a9e8dfbfad34211d1eb08b", "versionType": "git"}, {"lessThan": "edeefb111d6181a4aa278f415b005efe284b9489", "status": "affected", "version": "030d794bf49855f5e2a9e8dfbfad34211d1eb08b", "versionType": "git"}, {"lessThan": "3f019571928b269feebcff59926ec13294215e0e", "status": "affected", "version": "030d794bf49855f5e2a9e8dfbfad34211d1eb08b", "versionType": "git"}, {"lessThan": "5ce1ed6159731a41fdd0b03eedbed4e147036a5a", "status": "affected", "version": "030d794bf49855f5e2a9e8dfbfad34211d1eb08b", "versionType": "git"}]}, {"defaultStatus": "affected", "product": "Linux", "programFiles": ["net/sunrpc/auth_gss/gss_rpc_upcall.c", "net/sunrpc/auth_gss/gss_rpc_upcall.h", "net/sunrpc/auth_gss/svcauth_gss.c", "net/sunrpc/sunrpc_syms.c"], "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git", "vendor": "Linux", "versions": [{"status": "affected", "version": "3.10"}, {"lessThan": "3.10", "status": "unaffected", "version": "0", "versionType": "semver"}, {"lessThanOrEqual": "5.10.*", "status": "unaffected", "version": "5.10.270", "versionType": "semver"}, {"lessThanOrEqual": "5.15.*", "status": "unaffected", "version": "5.15.221", "versionType": "semver"}, {"lessThanOrEqual": "6.1.*", "status": "unaffected", "version": "6.1.188", "versionType": "semver"}, {"lessThanOrEqual": "6.6.*", "status": "unaffected", "version": "6.6.157", "versionType": "semver"}, {"lessThanOrEqual": "6.12.*", "status": "unaffected", "version": "6.12.109", "versionType": "semver"}, {"lessThanOrEqual": "6.18.*", "status": "unaffected", "version": "6.18.50", "versionType": "semver"}, {"lessThanOrEqual": "7.2.*", "status": "unaffected", "version": "7.2.4", "versionType": "semver"}, {"lessThanOrEqual": "*", "status": "unaffected", "version": "7.3", "versionType": "original_commit_for_fix"}]}], "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"}], "cveTags": [], "descriptions": [{"lang": "en", "value": "In the Linux kernel, the following vulnerability has been resolved:\n\nsunrpc: init gssp_lock before publishing proc entry\n\ncreate_use_gss_proxy_proc_entry() publishes /proc/net/rpc/use-gss-proxy\nvia proc_create_data() before init_gssp_clnt() runs mutex_init() on\nsn->gssp_lock. Once the dentry is linked under proc_subdir_lock it is\nimmediately reachable from userspace, so a write that lands in the\nwindow drives set_gssp_clnt() into mutex_lock() on a zero-initialized\nstruct mutex.\n\n create_use_gss_proxy_proc_entry(net)\n proc_create_data(\"use-gss-proxy\", ...) /* dentry live */\n init_gssp_clnt(sn)\n mutex_init(&sn->gssp_lock) /* too late */\n\n write_gssp()\n set_gssp_clnt(net)\n mutex_lock(&sn->gssp_lock) /* uninitialized */\n gssp_rpc_create(...)\n sn->gssp_clnt = clnt\n mutex_unlock(&sn->gssp_lock)\n\nThe window spans only the two statements between proc_create_data()\nreturning and init_gssp_clnt(), so a writer reaches it only if the\nregistering thread is preempted there while another task is already\nopening the freshly published file. register_pernet_subsys() runs in\npreemptible context under pernet_ops_rwsem, so that preemption is\npossible, and the window widens on auth_rpcgss module load, when the\nproc entry is created for every live net namespace whose tasks are\nalready running. A writer that wins the race locks a zero-filled\nstruct mutex. On CONFIG_DEBUG_MUTEXES the missing magic value trips a\n\"lock used without init\" splat; on a production kernel the fast path\nacquires the lock via CMPXCHG(owner, 0, current). In the latter case\na second writer that arrives before init_gssp_clnt() re-zeroes owner\ncan enter set_gssp_clnt() concurrently, shut down the first writer's\nclnt while it is still in use, and leak the loser's clnt.\n\nFix by initializing sn->gssp_lock in sunrpc_init_net() so its lifetime\nmatches the sunrpc_net it lives in. sn->gssp_clnt is already NULL from\nthe kzalloc that backs net_generic storage, so the lazy helper is no\nlonger needed; drop init_gssp_clnt(), its prototype, and the call from\ncreate_use_gss_proxy_proc_entry(). sunrpc.ko is a build-time\ndependency of auth_rpcgss.ko, so sunrpc_init_net() has always run on\nevery netns before any auth_gss pernet init can publish the proc\nentry."}], "id": "CVE-2026-89540", "lastModified": "2026-10-19T09:17:48.820", "metrics": {"cvssMetricV31": [{"cvssData": {"attackComplexity": "LOW", "attackVector": "LOCAL", "availabilityImpact": "HIGH", "baseScore": 7.8, "baseSeverity": "HIGH", "confidentialityImpact": "HIGH", "integrityImpact": "HIGH", "privilegesRequired": "LOW", "scope": "UNCHANGED", "userInteraction": "NONE", "vectorString": "CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H", "version": "3.1"}, "exploitabilityScore": 1.8, "impactScore": 5.9, "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "type": "Secondary"}], "ssvcV203": [{"source": "134c704f-9b21-4f2e-91b3-4a467353bcc0", "ssvcData": {"id": "CVE-2026-89540", "options": [{"exploitation": "none"}, {"automatable": "no"}, {"technicalImpact": "total"}], "role": "CISA Coordinator", "timestamp": "2026-10-16T19:23:23.496498Z", "version": "2.0.3"}}]}, "published": "2026-09-11T20:19:37.097", "references": [{"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "url": "https://git.kernel.org/stable/c/159a4fab7170badd6c4a553aef81cac079d6f4ee"}, {"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "url": "https://git.kernel.org/stable/c/3f019571928b269feebcff59926ec13294215e0e"}, {"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "url": "https://git.kernel.org/stable/c/5ce1ed6159731a41fdd0b03eedbed4e147036a5a"}, {"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "url": "https://git.kernel.org/stable/c/7f5bcdc8da15077ebe846c2756a5a17741021410"}, {"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "url": "https://git.kernel.org/stable/c/89c8e0733e8c46b7973503f15b1b31a8587d8030"}, {"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "url": "https://git.kernel.org/stable/c/b3526ae3351968f6726bcbe25d8d09973ad79109"}, {"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "url": "https://git.kernel.org/stable/c/edeefb111d6181a4aa278f415b005efe284b9489"}, {"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "url": "https://git.kernel.org/stable/c/f15b87521168c2a92cb1931f532cba422f856f01"}], "sourceIdentifier": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "vulnStatus": "Received"}

{"bugzilla": {"description": "kernel: Linux kernel: sunrpc denial of service and resource leak due to uninitialized mutex", "id": "2532132", "url": "https://bugzilla.redhat.com/show_bug.cgi?id=2532132"}, "csaw": false, "cvss3": {"cvss3_base_score": "4.1", "cvss3_scoring_vector": "CVSS:3.1/AV:L/AC:H/PR:H/UI:N/S:U/C:N/I:N/A:H", "status": "draft"}, "cwe": "CWE-909", "details": ["A flaw was found in the Linux kernel's sunrpc component. A race condition exists where the `gssp_lock` mutex is not initialized before its associated `/proc/net/rpc/use-gss-proxy` entry is published. This allows a local attacker to trigger a scenario where multiple writers can concurrently access the `set_gssp_clnt()` function, leading to a denial of service for the first writer's client and a resource leak."], "name": "CVE-2026-89540", "public_date": "2026-09-11T19:44:17Z", "references": ["https://www.cve.org/CVERecord?id=CVE-2026-89540\nhttps://nvd.nist.gov/vuln/detail/CVE-2026-89540\nhttps://git.kernel.org/stable/c/3f019571928b269feebcff59926ec13294215e0e\nhttps://git.kernel.org/stable/c/5ce1ed6159731a41fdd0b03eedbed4e147036a5a\nhttps://git.kernel.org/stable/c/edeefb111d6181a4aa278f415b005efe284b9489\nhttps://git.kernel.org/stable/c/f15b87521168c2a92cb1931f532cba422f856f01"], "threat_severity": "Moderate"}

{"affected": [{"configurations": [{"platform": null, "status": "affected", "versions": {"scheme": "code_commit", "value": "[030d794bf49855f5e2a9e8dfbfad34211d1eb08b,f15b87521168c2a92cb1931f532cba422f856f01)"}}, {"platform": null, "status": "affected", "versions": {"scheme": "code_commit", "value": "[030d794bf49855f5e2a9e8dfbfad34211d1eb08b,edeefb111d6181a4aa278f415b005efe284b9489)"}}, {"platform": null, "status": "affected", "versions": {"scheme": "code_commit", "value": "[030d794bf49855f5e2a9e8dfbfad34211d1eb08b,3f019571928b269feebcff59926ec13294215e0e)"}}, {"platform": null, "status": "affected", "versions": {"scheme": "code_commit", "value": "[030d794bf49855f5e2a9e8dfbfad34211d1eb08b,5ce1ed6159731a41fdd0b03eedbed4e147036a5a)"}}], "enrichment": {"confidence": 99.0, "confidence_source": "inferred", "scores": [{"score": 99.0, "source": "inferred"}, {"score": 100.0, "source": "matching"}]}, "original": {"product": "Linux", "source": "cna", "vendor": "Linux"}, "product": "linux_kernel", "vendor": "linux"}, {"configurations": [{"platform": null, "status": "affected", "versions": {"scheme": "generic", "value": "3.10"}}, {"platform": null, "status": "unaffected", "versions": {"scheme": "generic", "value": "[0,3.10)"}}, {"platform": null, "status": "unaffected", "versions": {"scheme": "semver", "value": "[6.12.109,6.13.0)"}}, {"platform": null, "status": "unaffected", "versions": {"scheme": "semver", "value": "[6.18.50,6.19.0)"}}, {"platform": null, "status": "unaffected", "versions": {"scheme": "semver", "value": "[7.2.4,7.3.0)"}}, {"platform": null, "status": "unaffected", "versions": {"scheme": "generic", "value": "[7.3-rc1,*]"}}], "enrichment": {"confidence": 99.0, "confidence_source": "inferred", "scores": [{"score": 99.0, "source": "inferred"}, {"score": 100.0, "source": "matching"}]}, "original": {"product": "Linux", "source": "cna", "vendor": "Linux"}, "product": "linux_kernel", "vendor": "linux"}], "created": "2026-09-12T09:30:12.577532+00:00", "updated": "2026-09-15T22:15:17.693839+00:00", "vendors": ["linux", "linux$PRODUCT$linux_kernel"]}