CVE-2026-89707

{"dataType": "CVE_RECORD", "dataVersion": "5.2", "cveMetadata": {"cveId": "CVE-2026-89707", "assignerOrgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "state": "PUBLISHED", "assignerShortName": "Linux", "dateReserved": "2026-09-11T19:38:34.751Z", "datePublished": "2026-09-11T19:46:23.293Z", "dateUpdated": "2026-10-30T12:32:46.529Z"}, "containers": {"cna": {"providerMetadata": {"orgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "shortName": "Linux", "dateUpdated": "2026-10-30T12:32:46.529Z"}, "descriptions": [{"lang": "en", "value": "In the Linux kernel, the following vulnerability has been resolved:\n\nnfsd: release path refs on follow_down() error\n\nnfsd_cross_mnt() initializes a local struct path with mntget() and\ndget() before calling follow_down(). On a negative return the error\narm jumps to out without releasing those references:\n\n err = follow_down(&path, follow_flags);\n if (err < 0)\n goto out;\n\nfollow_down() never drops the caller's entry-time refs on any error\nsub-case; for example a pre-cross d_manage() failure leaves path\nuntouched, so the mntget()/dget() taken on entry survive the call.\n\nEvery other early-exit arm in nfsd_cross_mnt() (other-namespace\nreturn, IS_ERR(exp2), and the success tail after the swap) already\ncalls path_put(&path); the err < 0 arm is the lone omission. The\nleak inflates mnt_count and d_count on each failed cross-mount,\nblocking umount and pinning dentries against the shrinker, and is\nreachable by any authenticated NFS client through nfsd_lookup_dentry\nor the NFSv4 READDIR encode path.\n\nFix by calling path_put(&path) before the goto out in the err < 0\narm so the entry-time refs are released on all follow_down() error\nreturns."}], "metrics": [{"cvssV3_1": {"version": "3.1", "vectorString": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H", "baseScore": 7.5, "baseSeverity": "HIGH"}, "scenarios": [{"lang": "en", "value": "AV:N - nfsd_cross_mnt() runs in the in-kernel NFS server on TCP/UDP 2049 from nfsd_lookup_dentry() (NFSv2/v3/v4 LOOKUP) and nfsd4_encode_entry4_fattr() (NFSv4 READDIR); a remote client reaches it with ordinary RPC requests.\nAC:L - On a typical nfsd export of autofs homes or nested mounts with crossmnt, an attacker can deterministically make follow_down() fail (autofs d_manage/automount error) by repeating LOOKUP/READDIR of failing mount triggers; no race or victim-controlled layout is required.\nPR:N - Default nfsd exports accept RPC_AUTH_NULL and RPC_AUTH_UNIX with no password; fh_verify only checks export IP policy, a MOUNT/PUTROOTFH filehandle, and directory execute, so no Linux account or capability on the server is required.\nUI:N - The attacker triggers the leak with their own NFS LOOKUP or READDIR RPCs; no victim mount, click, or other interactive action is required.\nS:U - The leak inflates dentry and vfsmount refcounts inside the nfsd host kernel and does not cross a VM, IOMMU, or other separate security authority.\nC:N - The bug only fails to path_put() the mntget/dget taken before follow_down(); it does not read kernel or file data or provide an information-disclosure primitive.\nI:N - The bug does not write attacker-controlled data or corrupt kernel objects; it only retains extra references on existing dentries and mounts.\nA:H - Each failed follow_down() permanently pins the dentry and vfsmount; repeated LOOKUPs of distinct autofs/mountpoint names leave unreclaimable dentries, block umount, and can exhaust kernel memory for a system-wide DoS."}]}], "affected": [{"product": "Linux", "vendor": "Linux", "defaultStatus": "unaffected", "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git", "programFiles": ["fs/nfsd/vfs.c"], "versions": [{"version": "cc53ce53c86924bfe98a12ea20b7465038a08792", "lessThan": "bdf5a0f88d21239d8f9f7519b87359ba95fd045c", "status": "affected", "versionType": "git"}, {"version": "cc53ce53c86924bfe98a12ea20b7465038a08792", "lessThan": "18847cbf5900f5c6c55bef5a6f7a34a1918d1181", "status": "affected", "versionType": "git"}, {"version": "cc53ce53c86924bfe98a12ea20b7465038a08792", "lessThan": "e301c5cdb0dc2c4aeffc0c055ea15615d9c51fdc", "status": "affected", "versionType": "git"}, {"version": "cc53ce53c86924bfe98a12ea20b7465038a08792", "lessThan": "085cfde7c2186acaad103f02d2c25435ad5224e9", "status": "affected", "versionType": "git"}, {"version": "cc53ce53c86924bfe98a12ea20b7465038a08792", "lessThan": "194316df81263519156ebe714c4a286bee00e5be", "status": "affected", "versionType": "git"}, {"version": "cc53ce53c86924bfe98a12ea20b7465038a08792", "lessThan": "467d56fd3ff57447a790c6dc3ede2d02a947d224", "status": "affected", "versionType": "git"}, {"version": "cc53ce53c86924bfe98a12ea20b7465038a08792", "lessThan": "2bc4343308d85ee4e0dd3877b384306c96f114c2", "status": "affected", "versionType": "git"}, {"version": "cc53ce53c86924bfe98a12ea20b7465038a08792", "lessThan": "6cba08dc1922140d260cfeb30bbda4ee1bf869d8", "status": "affected", "versionType": "git"}]}, {"product": "Linux", "vendor": "Linux", "defaultStatus": "affected", "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git", "programFiles": ["fs/nfsd/vfs.c"], "versions": [{"version": "2.6.38", "status": "affected"}, {"version": "0", "lessThan": "2.6.38", "status": "unaffected", "versionType": "semver"}, {"version": "5.10.273", "lessThanOrEqual": "5.10.*", "status": "unaffected", "versionType": "semver"}, {"version": "5.15.224", "lessThanOrEqual": "5.15.*", "status": "unaffected", "versionType": "semver"}, {"version": "6.1.191", "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": "2.6.38", "versionEndExcluding": "5.10.273"}, {"vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "2.6.38", "versionEndExcluding": "5.15.224"}, {"vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "2.6.38", "versionEndExcluding": "6.1.191"}, {"vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "2.6.38", "versionEndExcluding": "6.6.157"}, {"vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "2.6.38", "versionEndExcluding": "6.12.109"}, {"vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "2.6.38", "versionEndExcluding": "6.18.50"}, {"vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "2.6.38", "versionEndExcluding": "7.2.4"}, {"vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "2.6.38", "versionEndExcluding": "7.3"}]}]}], "references": [{"url": "https://git.kernel.org/stable/c/bdf5a0f88d21239d8f9f7519b87359ba95fd045c"}, {"url": "https://git.kernel.org/stable/c/18847cbf5900f5c6c55bef5a6f7a34a1918d1181"}, {"url": "https://git.kernel.org/stable/c/e301c5cdb0dc2c4aeffc0c055ea15615d9c51fdc"}, {"url": "https://git.kernel.org/stable/c/085cfde7c2186acaad103f02d2c25435ad5224e9"}, {"url": "https://git.kernel.org/stable/c/194316df81263519156ebe714c4a286bee00e5be"}, {"url": "https://git.kernel.org/stable/c/467d56fd3ff57447a790c6dc3ede2d02a947d224"}, {"url": "https://git.kernel.org/stable/c/2bc4343308d85ee4e0dd3877b384306c96f114c2"}, {"url": "https://git.kernel.org/stable/c/6cba08dc1922140d260cfeb30bbda4ee1bf869d8"}], "title": "nfsd: release path refs on follow_down() error", "x_generator": {"engine": "bippy-1.2.0"}}, "adp": [{"metrics": [{"other": {"type": "ssvc", "content": {"id": "CVE-2026-89707", "role": "CISA Coordinator", "options": [{"Exploitation": "none"}, {"Automatable": "yes"}, {"Technical Impact": "partial"}], "version": "2.0.3", "timestamp": "2026-10-16T19:26:16.926763Z"}}}], "title": "CISA ADP Vulnrichment", "providerMetadata": {"orgId": "134c704f-9b21-4f2e-91b3-4a467353bcc0", "shortName": "CISA-ADP", "dateUpdated": "2026-10-16T19:26:49.252Z"}}]}}

{"dataType": "CVE_RECORD", "containers": {"adp": [{"title": "CISA ADP Vulnrichment", "metrics": [{"other": {"type": "ssvc", "content": {"id": "CVE-2026-89707", "role": "CISA Coordinator", "options": [{"Exploitation": "none"}, {"Automatable": "yes"}, {"Technical Impact": "partial"}], "version": "2.0.3", "timestamp": "2026-10-16T19:26:16.926763Z"}}}], "providerMetadata": {"orgId": "134c704f-9b21-4f2e-91b3-4a467353bcc0", "shortName": "CISA-ADP", "dateUpdated": "2026-10-16T19:26:17.891Z"}}], "cna": {"title": "nfsd: release path refs on follow_down() error", "metrics": [{"cvssV3_1": {"version": "3.1", "baseScore": 7.5, "baseSeverity": "HIGH", "vectorString": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H"}, "scenarios": [{"lang": "en", "value": "AV:N - nfsd_cross_mnt() runs in the in-kernel NFS server on TCP/UDP 2049 from nfsd_lookup_dentry() (NFSv2/v3/v4 LOOKUP) and nfsd4_encode_entry4_fattr() (NFSv4 READDIR); a remote client reaches it with ordinary RPC requests.\nAC:L - On a typical nfsd export of autofs homes or nested mounts with crossmnt, an attacker can deterministically make follow_down() fail (autofs d_manage/automount error) by repeating LOOKUP/READDIR of failing mount triggers; no race or victim-controlled layout is required.\nPR:N - Default nfsd exports accept RPC_AUTH_NULL and RPC_AUTH_UNIX with no password; fh_verify only checks export IP policy, a MOUNT/PUTROOTFH filehandle, and directory execute, so no Linux account or capability on the server is required.\nUI:N - The attacker triggers the leak with their own NFS LOOKUP or READDIR RPCs; no victim mount, click, or other interactive action is required.\nS:U - The leak inflates dentry and vfsmount refcounts inside the nfsd host kernel and does not cross a VM, IOMMU, or other separate security authority.\nC:N - The bug only fails to path_put() the mntget/dget taken before follow_down(); it does not read kernel or file data or provide an information-disclosure primitive.\nI:N - The bug does not write attacker-controlled data or corrupt kernel objects; it only retains extra references on existing dentries and mounts.\nA:H - Each failed follow_down() permanently pins the dentry and vfsmount; repeated LOOKUPs of distinct autofs/mountpoint names leave unreclaimable dentries, block umount, and can exhaust kernel memory for a system-wide DoS."}]}], "affected": [{"repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git", "vendor": "Linux", "product": "Linux", "versions": [{"status": "affected", "version": "cc53ce53c86924bfe98a12ea20b7465038a08792", "lessThan": "bdf5a0f88d21239d8f9f7519b87359ba95fd045c", "versionType": "git"}, {"status": "affected", "version": "cc53ce53c86924bfe98a12ea20b7465038a08792", "lessThan": "18847cbf5900f5c6c55bef5a6f7a34a1918d1181", "versionType": "git"}, {"status": "affected", "version": "cc53ce53c86924bfe98a12ea20b7465038a08792", "lessThan": "e301c5cdb0dc2c4aeffc0c055ea15615d9c51fdc", "versionType": "git"}, {"status": "affected", "version": "cc53ce53c86924bfe98a12ea20b7465038a08792", "lessThan": "085cfde7c2186acaad103f02d2c25435ad5224e9", "versionType": "git"}, {"status": "affected", "version": "cc53ce53c86924bfe98a12ea20b7465038a08792", "lessThan": "194316df81263519156ebe714c4a286bee00e5be", "versionType": "git"}, {"status": "affected", "version": "cc53ce53c86924bfe98a12ea20b7465038a08792", "lessThan": "467d56fd3ff57447a790c6dc3ede2d02a947d224", "versionType": "git"}, {"status": "affected", "version": "cc53ce53c86924bfe98a12ea20b7465038a08792", "lessThan": "2bc4343308d85ee4e0dd3877b384306c96f114c2", "versionType": "git"}, {"status": "affected", "version": "cc53ce53c86924bfe98a12ea20b7465038a08792", "lessThan": "6cba08dc1922140d260cfeb30bbda4ee1bf869d8", "versionType": "git"}], "programFiles": ["fs/nfsd/vfs.c"], "defaultStatus": "unaffected"}, {"repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git", "vendor": "Linux", "product": "Linux", "versions": [{"status": "affected", "version": "2.6.38"}, {"status": "unaffected", "version": "0", "lessThan": "2.6.38", "versionType": "semver"}, {"status": "unaffected", "version": "5.10.273", "versionType": "semver", "lessThanOrEqual": "5.10.*"}, {"status": "unaffected", "version": "5.15.224", "versionType": "semver", "lessThanOrEqual": "5.15.*"}, {"status": "unaffected", "version": "6.1.191", "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": ["fs/nfsd/vfs.c"], "defaultStatus": "affected"}], "references": [{"url": "https://git.kernel.org/stable/c/bdf5a0f88d21239d8f9f7519b87359ba95fd045c"}, {"url": "https://git.kernel.org/stable/c/18847cbf5900f5c6c55bef5a6f7a34a1918d1181"}, {"url": "https://git.kernel.org/stable/c/e301c5cdb0dc2c4aeffc0c055ea15615d9c51fdc"}, {"url": "https://git.kernel.org/stable/c/085cfde7c2186acaad103f02d2c25435ad5224e9"}, {"url": "https://git.kernel.org/stable/c/194316df81263519156ebe714c4a286bee00e5be"}, {"url": "https://git.kernel.org/stable/c/467d56fd3ff57447a790c6dc3ede2d02a947d224"}, {"url": "https://git.kernel.org/stable/c/2bc4343308d85ee4e0dd3877b384306c96f114c2"}, {"url": "https://git.kernel.org/stable/c/6cba08dc1922140d260cfeb30bbda4ee1bf869d8"}], "x_generator": {"engine": "bippy-1.2.0"}, "descriptions": [{"lang": "en", "value": "In the Linux kernel, the following vulnerability has been resolved:\n\nnfsd: release path refs on follow_down() error\n\nnfsd_cross_mnt() initializes a local struct path with mntget() and\ndget() before calling follow_down(). On a negative return the error\narm jumps to out without releasing those references:\n\n err = follow_down(&path, follow_flags);\n if (err < 0)\n goto out;\n\nfollow_down() never drops the caller's entry-time refs on any error\nsub-case; for example a pre-cross d_manage() failure leaves path\nuntouched, so the mntget()/dget() taken on entry survive the call.\n\nEvery other early-exit arm in nfsd_cross_mnt() (other-namespace\nreturn, IS_ERR(exp2), and the success tail after the swap) already\ncalls path_put(&path); the err < 0 arm is the lone omission. The\nleak inflates mnt_count and d_count on each failed cross-mount,\nblocking umount and pinning dentries against the shrinker, and is\nreachable by any authenticated NFS client through nfsd_lookup_dentry\nor the NFSv4 READDIR encode path.\n\nFix by calling path_put(&path) before the goto out in the err < 0\narm so the entry-time refs are released on all follow_down() error\nreturns."}], "cpeApplicability": [{"nodes": [{"negate": false, "cpeMatch": [{"criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "vulnerable": true, "versionEndExcluding": "5.10.273", "versionStartIncluding": "2.6.38"}, {"criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "vulnerable": true, "versionEndExcluding": "5.15.224", "versionStartIncluding": "2.6.38"}, {"criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "vulnerable": true, "versionEndExcluding": "6.1.191", "versionStartIncluding": "2.6.38"}, {"criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "vulnerable": true, "versionEndExcluding": "6.6.157", "versionStartIncluding": "2.6.38"}, {"criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "vulnerable": true, "versionEndExcluding": "6.12.109", "versionStartIncluding": "2.6.38"}, {"criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "vulnerable": true, "versionEndExcluding": "6.18.50", "versionStartIncluding": "2.6.38"}, {"criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "vulnerable": true, "versionEndExcluding": "7.2.4", "versionStartIncluding": "2.6.38"}, {"criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "vulnerable": true, "versionEndExcluding": "7.3", "versionStartIncluding": "2.6.38"}], "operator": "OR"}]}], "providerMetadata": {"orgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "shortName": "Linux", "dateUpdated": "2026-10-30T12:32:46.529Z"}}}, "cveMetadata": {"cveId": "CVE-2026-89707", "state": "PUBLISHED", "dateUpdated": "2026-10-30T12:32:46.529Z", "dateReserved": "2026-09-11T19:38:34.751Z", "assignerOrgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "datePublished": "2026-09-11T19:46:23.293Z", "assignerShortName": "Linux"}, "dataVersion": "5.2"}

{"affected": [{"affectedData": [{"defaultStatus": "unaffected", "product": "Linux", "programFiles": ["fs/nfsd/vfs.c"], "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git", "vendor": "Linux", "versions": [{"lessThan": "bdf5a0f88d21239d8f9f7519b87359ba95fd045c", "status": "affected", "version": "cc53ce53c86924bfe98a12ea20b7465038a08792", "versionType": "git"}, {"lessThan": "18847cbf5900f5c6c55bef5a6f7a34a1918d1181", "status": "affected", "version": "cc53ce53c86924bfe98a12ea20b7465038a08792", "versionType": "git"}, {"lessThan": "e301c5cdb0dc2c4aeffc0c055ea15615d9c51fdc", "status": "affected", "version": "cc53ce53c86924bfe98a12ea20b7465038a08792", "versionType": "git"}, {"lessThan": "085cfde7c2186acaad103f02d2c25435ad5224e9", "status": "affected", "version": "cc53ce53c86924bfe98a12ea20b7465038a08792", "versionType": "git"}, {"lessThan": "194316df81263519156ebe714c4a286bee00e5be", "status": "affected", "version": "cc53ce53c86924bfe98a12ea20b7465038a08792", "versionType": "git"}, {"lessThan": "467d56fd3ff57447a790c6dc3ede2d02a947d224", "status": "affected", "version": "cc53ce53c86924bfe98a12ea20b7465038a08792", "versionType": "git"}, {"lessThan": "2bc4343308d85ee4e0dd3877b384306c96f114c2", "status": "affected", "version": "cc53ce53c86924bfe98a12ea20b7465038a08792", "versionType": "git"}, {"lessThan": "6cba08dc1922140d260cfeb30bbda4ee1bf869d8", "status": "affected", "version": "cc53ce53c86924bfe98a12ea20b7465038a08792", "versionType": "git"}]}, {"defaultStatus": "affected", "product": "Linux", "programFiles": ["fs/nfsd/vfs.c"], "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git", "vendor": "Linux", "versions": [{"status": "affected", "version": "2.6.38"}, {"lessThan": "2.6.38", "status": "unaffected", "version": "0", "versionType": "semver"}, {"lessThanOrEqual": "5.10.*", "status": "unaffected", "version": "5.10.273", "versionType": "semver"}, {"lessThanOrEqual": "5.15.*", "status": "unaffected", "version": "5.15.224", "versionType": "semver"}, {"lessThanOrEqual": "6.1.*", "status": "unaffected", "version": "6.1.191", "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\nnfsd: release path refs on follow_down() error\n\nnfsd_cross_mnt() initializes a local struct path with mntget() and\ndget() before calling follow_down(). On a negative return the error\narm jumps to out without releasing those references:\n\n err = follow_down(&path, follow_flags);\n if (err < 0)\n goto out;\n\nfollow_down() never drops the caller's entry-time refs on any error\nsub-case; for example a pre-cross d_manage() failure leaves path\nuntouched, so the mntget()/dget() taken on entry survive the call.\n\nEvery other early-exit arm in nfsd_cross_mnt() (other-namespace\nreturn, IS_ERR(exp2), and the success tail after the swap) already\ncalls path_put(&path); the err < 0 arm is the lone omission. The\nleak inflates mnt_count and d_count on each failed cross-mount,\nblocking umount and pinning dentries against the shrinker, and is\nreachable by any authenticated NFS client through nfsd_lookup_dentry\nor the NFSv4 READDIR encode path.\n\nFix by calling path_put(&path) before the goto out in the err < 0\narm so the entry-time refs are released on all follow_down() error\nreturns."}], "id": "CVE-2026-89707", "lastModified": "2026-10-30T13:20:26.963", "metrics": {"cvssMetricV31": [{"cvssData": {"attackComplexity": "LOW", "attackVector": "NETWORK", "availabilityImpact": "HIGH", "baseScore": 7.5, "baseSeverity": "HIGH", "confidentialityImpact": "NONE", "integrityImpact": "NONE", "privilegesRequired": "NONE", "scope": "UNCHANGED", "userInteraction": "NONE", "vectorString": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H", "version": "3.1"}, "exploitabilityScore": 3.9, "impactScore": 3.6, "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "type": "Secondary"}], "ssvcV203": [{"source": "134c704f-9b21-4f2e-91b3-4a467353bcc0", "ssvcData": {"id": "CVE-2026-89707", "options": [{"exploitation": "none"}, {"automatable": "yes"}, {"technicalImpact": "partial"}], "role": "CISA Coordinator", "timestamp": "2026-10-16T19:26:16.926763Z", "version": "2.0.3"}}]}, "published": "2026-09-11T20:19:58.017", "references": [{"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "url": "https://git.kernel.org/stable/c/085cfde7c2186acaad103f02d2c25435ad5224e9"}, {"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "url": "https://git.kernel.org/stable/c/18847cbf5900f5c6c55bef5a6f7a34a1918d1181"}, {"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "url": "https://git.kernel.org/stable/c/194316df81263519156ebe714c4a286bee00e5be"}, {"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "url": "https://git.kernel.org/stable/c/2bc4343308d85ee4e0dd3877b384306c96f114c2"}, {"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "url": "https://git.kernel.org/stable/c/467d56fd3ff57447a790c6dc3ede2d02a947d224"}, {"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "url": "https://git.kernel.org/stable/c/6cba08dc1922140d260cfeb30bbda4ee1bf869d8"}, {"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "url": "https://git.kernel.org/stable/c/bdf5a0f88d21239d8f9f7519b87359ba95fd045c"}, {"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "url": "https://git.kernel.org/stable/c/e301c5cdb0dc2c4aeffc0c055ea15615d9c51fdc"}], "sourceIdentifier": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "vulnStatus": "Received"}

{"bugzilla": {"description": "kernel: Linux kernel nfsd: Denial of Service due to reference count leak", "id": "2532441", "url": "https://bugzilla.redhat.com/show_bug.cgi?id=2532441"}, "csaw": false, "cvss3": {"cvss3_base_score": "5.3", "cvss3_scoring_vector": "CVSS:3.1/AV:N/AC:H/PR:L/UI:N/S:U/C:N/I:N/A:H", "status": "draft"}, "cwe": "CWE-911", "details": ["A flaw was found in the Linux kernel's nfsd component. An authenticated Network File System (NFS) client can exploit this vulnerability by triggering a failed cross-mount operation through `nfsd_lookup_dentry` or the NFSv4 READDIR encode path. This leads to a reference count leak, which inflates `mnt_count` and `d_count`, blocking unmounting operations and pinning directory entries against the shrinker. This can result in a Denial of Service (DoS) condition."], "name": "CVE-2026-89707", "public_date": "2026-09-11T19:46:23Z", "references": ["https://www.cve.org/CVERecord?id=CVE-2026-89707\nhttps://nvd.nist.gov/vuln/detail/CVE-2026-89707\nhttps://git.kernel.org/stable/c/194316df81263519156ebe714c4a286bee00e5be\nhttps://git.kernel.org/stable/c/2bc4343308d85ee4e0dd3877b384306c96f114c2\nhttps://git.kernel.org/stable/c/467d56fd3ff57447a790c6dc3ede2d02a947d224\nhttps://git.kernel.org/stable/c/6cba08dc1922140d260cfeb30bbda4ee1bf869d8"], "threat_severity": "Moderate"}

{"affected": [{"configurations": [{"platform": null, "status": "affected", "versions": {"scheme": "code_commit", "value": "[cc53ce53c86924bfe98a12ea20b7465038a08792,194316df81263519156ebe714c4a286bee00e5be)"}}, {"platform": null, "status": "affected", "versions": {"scheme": "code_commit", "value": "[cc53ce53c86924bfe98a12ea20b7465038a08792,467d56fd3ff57447a790c6dc3ede2d02a947d224)"}}, {"platform": null, "status": "affected", "versions": {"scheme": "code_commit", "value": "[cc53ce53c86924bfe98a12ea20b7465038a08792,2bc4343308d85ee4e0dd3877b384306c96f114c2)"}}, {"platform": null, "status": "affected", "versions": {"scheme": "code_commit", "value": "[cc53ce53c86924bfe98a12ea20b7465038a08792,6cba08dc1922140d260cfeb30bbda4ee1bf869d8)"}}], "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": "semver", "value": "2.6.38"}}, {"platform": null, "status": "unaffected", "versions": {"scheme": "semver", "value": "[0,2.6.38)"}}, {"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": "semver", "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": "2026-09-12T08:15:07.026618+00:00", "updated": "2026-09-15T19:45:07.195685+00:00", "vendors": ["linux", "linux$PRODUCT$linux_kernel"]}