CVE-2026-98983

{"dataType": "CVE_RECORD", "dataVersion": "5.2", "cveMetadata": {"cveId": "CVE-2026-98983", "assignerOrgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "state": "PUBLISHED", "assignerShortName": "Linux", "dateReserved": "2026-09-25T10:25:14.384Z", "datePublished": "2026-10-23T12:20:00.918Z", "dateUpdated": "2026-10-23T12:20:00.918Z"}, "containers": {"cna": {"providerMetadata": {"orgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "shortName": "Linux", "dateUpdated": "2026-10-23T12:20:00.918Z"}, "descriptions": [{"lang": "en", "value": "In the Linux kernel, the following vulnerability has been resolved:\n\nunshare: don't drop active namespace references that were never taken\n\nActive references on the namespaces of an nsproxy are taken when the\nnsproxy is installed into a task in switch_task_namespaces() and\ncopy_namespaces() and dropped again by put_nsproxy() through\ndeactivate_nsproxy().\n\nBut ksys_unshare() calls put_nsproxy() on an nsproxy that was never\ninstalled when set_cred_ucounts() fails. The new namespaces of that\nnsproxy go from zero to minus one and the namespaces shared with the\ncaller lose a reference that belongs to the nsproxy the caller keeps\nusing:\n\n WARNING: kernel/nscommon.c:171 at __ns_ref_active_put+0x1cd/0x230\n nsproxy_ns_active_put\n deactivate_nsproxy\n ksys_unshare\n\nAfterwards the namespaces the caller lives in aren't listed by listns()\nanymore. set_cred_ucounts() only fails when alloc_ucounts() can't\nallocate and it only allocates when the real uid of the caller differs\nfrom its effective uid.\n\nCommit cefd55bd2159 (\"nsproxy: fix free_nsproxy() and simplify\ncreate_new_namespaces()\") separated the two cases on purpose.\nnsproxy_free() frees an nsproxy that was prepared but never installed\nand that's what a failed setns() uses in put_nsset(). Export it and use\nit for a failed unshare() as well."}], "affected": [{"product": "Linux", "vendor": "Linux", "defaultStatus": "unaffected", "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git", "programFiles": ["include/linux/nsproxy.h", "kernel/fork.c", "kernel/nsproxy.c"], "versions": [{"version": "a98621a0f187a934c115dcfe79a49520ae892111", "lessThan": "56fe03a0c05dba4c5f6a23c391f96de1614a098c", "status": "affected", "versionType": "git"}, {"version": "a98621a0f187a934c115dcfe79a49520ae892111", "lessThan": "0b6f31a3c0b16066f812e94b52a704174a6f23cd", "status": "affected", "versionType": "git"}, {"version": "27ae6b17c9ba7ff353ab0906297f08aa845782b4", "status": "affected", "versionType": "git"}, {"version": "297261b343371c4f0b31055d53d285138ec21565", "status": "affected", "versionType": "git"}, {"version": "813a47b0309097da71781ee4ac11922e39b67d55", "status": "affected", "versionType": "git"}, {"version": "6e608e3e5ce12ce7fd21e46212eccca37f917d0e", "status": "affected", "versionType": "git"}, {"version": "a261fccdb4ac58ec5ba6aa1d92a6cc418fff301f", "status": "affected", "versionType": "git"}, {"version": "665dc1ed16357988d439fc5bbc860ee36f540d81", "status": "affected", "versionType": "git"}, {"version": "5.15.209", "lessThan": "5.16", "status": "affected", "versionType": "semver"}, {"version": "6.1.175", "lessThan": "6.2", "status": "affected", "versionType": "semver"}, {"version": "6.6.141", "lessThan": "6.7", "status": "affected", "versionType": "semver"}, {"version": "6.12.91", "lessThan": "6.13", "status": "affected", "versionType": "semver"}, {"version": "6.18.33", "lessThan": "6.19", "status": "affected", "versionType": "semver"}, {"version": "7.0.10", "lessThan": "7.1", "status": "affected", "versionType": "semver"}]}, {"product": "Linux", "vendor": "Linux", "defaultStatus": "affected", "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git", "programFiles": ["include/linux/nsproxy.h", "kernel/fork.c", "kernel/nsproxy.c"], "versions": [{"version": "7.1", "status": "affected"}, {"version": "0", "lessThan": "7.1", "status": "unaffected", "versionType": "semver"}, {"version": "7.2.11", "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": "7.1", "versionEndExcluding": "7.2.11"}, {"vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "7.1", "versionEndExcluding": "7.3"}, {"vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "5.15.209"}, {"vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "6.1.175"}, {"vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "6.6.141"}, {"vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "6.12.91"}, {"vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "6.18.33"}, {"vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "7.0.10"}]}]}], "references": [{"url": "https://git.kernel.org/stable/c/56fe03a0c05dba4c5f6a23c391f96de1614a098c"}, {"url": "https://git.kernel.org/stable/c/0b6f31a3c0b16066f812e94b52a704174a6f23cd"}], "title": "unshare: don't drop active namespace references that were never taken", "x_generator": {"engine": "bippy-1.2.0"}}}}

{}

{"affected": [{"affectedData": [{"defaultStatus": "unaffected", "product": "Linux", "programFiles": ["include/linux/nsproxy.h", "kernel/fork.c", "kernel/nsproxy.c"], "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git", "vendor": "Linux", "versions": [{"lessThan": "56fe03a0c05dba4c5f6a23c391f96de1614a098c", "status": "affected", "version": "a98621a0f187a934c115dcfe79a49520ae892111", "versionType": "git"}, {"lessThan": "0b6f31a3c0b16066f812e94b52a704174a6f23cd", "status": "affected", "version": "a98621a0f187a934c115dcfe79a49520ae892111", "versionType": "git"}, {"status": "affected", "version": "27ae6b17c9ba7ff353ab0906297f08aa845782b4", "versionType": "git"}, {"status": "affected", "version": "297261b343371c4f0b31055d53d285138ec21565", "versionType": "git"}, {"status": "affected", "version": "813a47b0309097da71781ee4ac11922e39b67d55", "versionType": "git"}, {"status": "affected", "version": "6e608e3e5ce12ce7fd21e46212eccca37f917d0e", "versionType": "git"}, {"status": "affected", "version": "a261fccdb4ac58ec5ba6aa1d92a6cc418fff301f", "versionType": "git"}, {"status": "affected", "version": "665dc1ed16357988d439fc5bbc860ee36f540d81", "versionType": "git"}, {"lessThan": "5.16", "status": "affected", "version": "5.15.209", "versionType": "semver"}, {"lessThan": "6.2", "status": "affected", "version": "6.1.175", "versionType": "semver"}, {"lessThan": "6.7", "status": "affected", "version": "6.6.141", "versionType": "semver"}, {"lessThan": "6.13", "status": "affected", "version": "6.12.91", "versionType": "semver"}, {"lessThan": "6.19", "status": "affected", "version": "6.18.33", "versionType": "semver"}, {"lessThan": "7.1", "status": "affected", "version": "7.0.10", "versionType": "semver"}]}, {"defaultStatus": "affected", "product": "Linux", "programFiles": ["include/linux/nsproxy.h", "kernel/fork.c", "kernel/nsproxy.c"], "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git", "vendor": "Linux", "versions": [{"status": "affected", "version": "7.1"}, {"lessThan": "7.1", "status": "unaffected", "version": "0", "versionType": "semver"}, {"lessThanOrEqual": "7.2.*", "status": "unaffected", "version": "7.2.11", "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\nunshare: don't drop active namespace references that were never taken\n\nActive references on the namespaces of an nsproxy are taken when the\nnsproxy is installed into a task in switch_task_namespaces() and\ncopy_namespaces() and dropped again by put_nsproxy() through\ndeactivate_nsproxy().\n\nBut ksys_unshare() calls put_nsproxy() on an nsproxy that was never\ninstalled when set_cred_ucounts() fails. The new namespaces of that\nnsproxy go from zero to minus one and the namespaces shared with the\ncaller lose a reference that belongs to the nsproxy the caller keeps\nusing:\n\n WARNING: kernel/nscommon.c:171 at __ns_ref_active_put+0x1cd/0x230\n nsproxy_ns_active_put\n deactivate_nsproxy\n ksys_unshare\n\nAfterwards the namespaces the caller lives in aren't listed by listns()\nanymore. set_cred_ucounts() only fails when alloc_ucounts() can't\nallocate and it only allocates when the real uid of the caller differs\nfrom its effective uid.\n\nCommit cefd55bd2159 (\"nsproxy: fix free_nsproxy() and simplify\ncreate_new_namespaces()\") separated the two cases on purpose.\nnsproxy_free() frees an nsproxy that was prepared but never installed\nand that's what a failed setns() uses in put_nsset(). Export it and use\nit for a failed unshare() as well."}], "id": "CVE-2026-98983", "lastModified": "2026-10-23T13:17:20.160", "metrics": {}, "published": "2026-10-23T13:17:20.160", "references": [{"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "url": "https://git.kernel.org/stable/c/0b6f31a3c0b16066f812e94b52a704174a6f23cd"}, {"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "url": "https://git.kernel.org/stable/c/56fe03a0c05dba4c5f6a23c391f96de1614a098c"}], "sourceIdentifier": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "vulnStatus": "Received"}

{"bugzilla": {"description": "kernel: unshare: don't drop active namespace references that were never taken", "id": "2559746", "url": "https://bugzilla.redhat.com/show_bug.cgi?id=2559746"}, "csaw": false, "cvss3": {"cvss3_base_score": "4.7", "cvss3_scoring_vector": "CVSS:3.1/AV:L/AC:H/PR:L/UI:N/S:U/C:N/I:N/A:H", "status": "draft"}, "cwe": "CWE-911", "details": ["In the Linux kernel, the following vulnerability has been resolved:\nunshare: don't drop active namespace references that were never taken\nActive references on the namespaces of an nsproxy are taken when the\nnsproxy is installed into a task in switch_task_namespaces() and\ncopy_namespaces() and dropped again by put_nsproxy() through\ndeactivate_nsproxy().\nBut ksys_unshare() calls put_nsproxy() on an nsproxy that was never\ninstalled when set_cred_ucounts() fails. The new namespaces of that\nnsproxy go from zero to minus one and the namespaces shared with the\ncaller lose a reference that belongs to the nsproxy the caller keeps\nusing:\nWARNING: kernel/nscommon.c:171 at __ns_ref_active_put+0x1cd/0x230\nnsproxy_ns_active_put\ndeactivate_nsproxy\nksys_unshare\nAfterwards the namespaces the caller lives in aren't listed by listns()\nanymore. set_cred_ucounts() only fails when alloc_ucounts() can't\nallocate and it only allocates when the real uid of the caller differs\nfrom its effective uid.\nCommit cefd55bd2159 (\"nsproxy: fix free_nsproxy() and simplify\ncreate_new_namespaces()\") separated the two cases on purpose.\nnsproxy_free() frees an nsproxy that was prepared but never installed\nand that's what a failed setns() uses in put_nsset(). Export it and use\nit for a failed unshare() as well.", "A flaw was found in the Linux kernel. During a failed namespace unshare operation, the kernel improperly decrements reference counters for namespaces that were never fully established. A local attacker could exploit this flaw by triggering specific credential allocation failures, leading to reference count inconsistencies, system instability, or a Denial of Service (DoS)."], "name": "CVE-2026-98983", "package_state": [{"cpe": "cpe:/o:redhat:enterprise_linux:10", "fix_state": "Not affected", "package_name": "kernel", "product_name": "Red Hat Enterprise Linux 10"}, {"cpe": "cpe:/o:redhat:enterprise_linux:6", "fix_state": "Out of support scope", "package_name": "kernel", "product_name": "Red Hat Enterprise Linux 6"}, {"cpe": "cpe:/o:redhat:enterprise_linux:7", "fix_state": "Not affected", "package_name": "kernel", "product_name": "Red Hat Enterprise Linux 7"}, {"cpe": "cpe:/o:redhat:enterprise_linux:7", "fix_state": "Not affected", "package_name": "kernel-rt", "product_name": "Red Hat Enterprise Linux 7"}, {"cpe": "cpe:/o:redhat:enterprise_linux:8", "fix_state": "Not affected", "package_name": "kernel", "product_name": "Red Hat Enterprise Linux 8"}, {"cpe": "cpe:/o:redhat:enterprise_linux:8", "fix_state": "Not affected", "package_name": "kernel-rt", "product_name": "Red Hat Enterprise Linux 8"}, {"cpe": "cpe:/o:redhat:enterprise_linux:9", "fix_state": "Not affected", "package_name": "kernel", "product_name": "Red Hat Enterprise Linux 9"}, {"cpe": "cpe:/o:redhat:enterprise_linux:9", "fix_state": "Not affected", "package_name": "kernel-rt", "product_name": "Red Hat Enterprise Linux 9"}, {"cpe": "cpe:/a:redhat:openshift:4", "fix_state": "Not affected", "package_name": "openshift/ose-rhel-coreos-8", "product_name": "Red Hat OpenShift Container Platform 4"}, {"cpe": "cpe:/a:redhat:openshift:4", "fix_state": "Not affected", "package_name": "openshift/ose-rhel-coreos-9", "product_name": "Red Hat OpenShift Container Platform 4"}], "public_date": "2026-10-23T00:00:00Z", "references": ["https://www.cve.org/CVERecord?id=CVE-2026-98983\nhttps://nvd.nist.gov/vuln/detail/CVE-2026-98983\nhttps://git.kernel.org/pub/scm/linux/security/vulns.git/plain/cve/published/2026/CVE-2026-98983.mbox"], "threat_severity": "Moderate"}

{"affected": [{"configurations": [{"platform": null, "status": "affected", "versions": {"scheme": "code_commit", "value": "[a98621a0f187a934c115dcfe79a49520ae892111,56fe03a0c05dba4c5f6a23c391f96de1614a098c)"}}, {"platform": null, "status": "affected", "versions": {"scheme": "code_commit", "value": "[a98621a0f187a934c115dcfe79a49520ae892111,0b6f31a3c0b16066f812e94b52a704174a6f23cd)"}}, {"platform": null, "status": "affected", "versions": {"scheme": "code_commit", "value": "27ae6b17c9ba7ff353ab0906297f08aa845782b4"}}, {"platform": null, "status": "affected", "versions": {"scheme": "code_commit", "value": "297261b343371c4f0b31055d53d285138ec21565"}}, {"platform": null, "status": "affected", "versions": {"scheme": "code_commit", "value": "813a47b0309097da71781ee4ac11922e39b67d55"}}, {"platform": null, "status": "affected", "versions": {"scheme": "code_commit", "value": "6e608e3e5ce12ce7fd21e46212eccca37f917d0e"}}, {"platform": null, "status": "affected", "versions": {"scheme": "code_commit", "value": "a261fccdb4ac58ec5ba6aa1d92a6cc418fff301f"}}, {"platform": null, "status": "affected", "versions": {"scheme": "code_commit", "value": "665dc1ed16357988d439fc5bbc860ee36f540d81"}}, {"platform": null, "status": "affected", "versions": {"scheme": "semver", "value": "[5.15.209,5.16)"}}, {"platform": null, "status": "affected", "versions": {"scheme": "semver", "value": "[6.1.175,6.2)"}}, {"platform": null, "status": "affected", "versions": {"scheme": "semver", "value": "[6.6.141,6.7)"}}, {"platform": null, "status": "affected", "versions": {"scheme": "semver", "value": "[6.12.91,6.13)"}}, {"platform": null, "status": "affected", "versions": {"scheme": "semver", "value": "[6.18.33,6.19)"}}, {"platform": null, "status": "affected", "versions": {"scheme": "semver", "value": "[7.0.10,7.1)"}}], "enrichment": {"confidence": 100.0, "confidence_source": "matching", "scores": [{"score": 100.0, "source": "matching"}]}, "original": {"product": "Linux", "source": "cna", "vendor": "Linux"}, "product": "linux", "vendor": "linux"}, {"configurations": [{"platform": null, "status": "affected", "versions": {"scheme": "generic", "value": "7.1"}}, {"platform": null, "status": "unaffected", "versions": {"scheme": "generic", "value": "[0,7.1)"}}, {"platform": null, "status": "unaffected", "versions": {"scheme": "semver", "value": "[7.2.11,7.3.0)"}}, {"platform": null, "status": "unaffected", "versions": {"scheme": "generic", "value": "[7.3,*]"}}], "enrichment": {"confidence": 100.0, "confidence_source": "matching", "scores": [{"score": 100.0, "source": "matching"}]}, "original": {"product": "Linux", "source": "cna", "vendor": "Linux"}, "product": "linux", "vendor": "linux"}, {"configurations": [{"platform": null, "status": "affected", "versions": {"scheme": "code_commit", "value": "[a98621a0f187a934c115dcfe79a49520ae892111,56fe03a0c05dba4c5f6a23c391f96de1614a098c)"}}, {"platform": null, "status": "affected", "versions": {"scheme": "code_commit", "value": "[a98621a0f187a934c115dcfe79a49520ae892111,0b6f31a3c0b16066f812e94b52a704174a6f23cd)"}}, {"platform": null, "status": "affected", "versions": {"scheme": "code_commit", "value": "27ae6b17c9ba7ff353ab0906297f08aa845782b4"}}, {"platform": null, "status": "affected", "versions": {"scheme": "code_commit", "value": "297261b343371c4f0b31055d53d285138ec21565"}}, {"platform": null, "status": "affected", "versions": {"scheme": "code_commit", "value": "813a47b0309097da71781ee4ac11922e39b67d55"}}, {"platform": null, "status": "affected", "versions": {"scheme": "code_commit", "value": "6e608e3e5ce12ce7fd21e46212eccca37f917d0e"}}, {"platform": null, "status": "affected", "versions": {"scheme": "code_commit", "value": "a261fccdb4ac58ec5ba6aa1d92a6cc418fff301f"}}, {"platform": null, "status": "affected", "versions": {"scheme": "code_commit", "value": "665dc1ed16357988d439fc5bbc860ee36f540d81"}}, {"platform": null, "status": "affected", "versions": {"scheme": "semver", "value": "[5.15.209,5.16)"}}, {"platform": null, "status": "affected", "versions": {"scheme": "semver", "value": "[6.1.175,6.2)"}}, {"platform": null, "status": "affected", "versions": {"scheme": "semver", "value": "[6.6.141,6.7)"}}, {"platform": null, "status": "affected", "versions": {"scheme": "semver", "value": "[6.12.91,6.13)"}}, {"platform": null, "status": "affected", "versions": {"scheme": "semver", "value": "[6.18.33,6.19)"}}, {"platform": null, "status": "affected", "versions": {"scheme": "semver", "value": "[7.0.10,7.1)"}}], "enrichment": {"confidence": 100.0, "confidence_source": "matching", "scores": [{"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": "7.1"}}, {"platform": null, "status": "unaffected", "versions": {"scheme": "generic", "value": "[0,7.1)"}}, {"platform": null, "status": "unaffected", "versions": {"scheme": "semver", "value": "[7.2.11,7.3.0)"}}, {"platform": null, "status": "unaffected", "versions": {"scheme": "generic", "value": "[7.3,*]"}}], "enrichment": {"confidence": 100.0, "confidence_source": "matching", "scores": [{"score": 100.0, "source": "matching"}]}, "original": {"product": "Linux", "source": "cna", "vendor": "Linux"}, "product": "linux_kernel", "vendor": "linux"}], "created": "2026-10-23T17:00:15.616641+00:00", "updated": "2026-10-29T23:00:06.190292+00:00", "vendors": ["linux", "linux$PRODUCT$linux", "linux$PRODUCT$linux_kernel"], "weaknesses": ["CWE-911"]}