{"schema":"threatline.record/2","record":{"id":"CVE-2026-98983","aliases":[],"summary":"unshare: don't drop active namespace references that were never taken","details":"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.","categories":["Operating systems"],"product":"Linux","vendor":"Linux","ecosystem":null,"affected_ranges":[{"source":"CVE List","source_url":"https://www.cve.org/CVERecord?id=CVE-2026-98983","source_modified_at":"2026-10-23T12:20:00.918Z","fetched_at":"2026-10-23T18:42:43.628194Z","product":"Linux","vendor":"Linux","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"}],"defaultStatus":"unaffected"},{"source":"CVE List","source_url":"https://www.cve.org/CVERecord?id=CVE-2026-98983","source_modified_at":"2026-10-23T12:20:00.918Z","fetched_at":"2026-10-23T18:42:43.628194Z","product":"Linux","vendor":"Linux","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"}],"defaultStatus":"affected"}],"fixed_versions":[{"source":"CVE List","source_url":"https://www.cve.org/CVERecord?id=CVE-2026-98983","source_modified_at":"2026-10-23T12:20:00.918Z","fetched_at":"2026-10-23T18:42:43.628194Z","package":{"name":"Linux","ecosystem":null},"version":"56fe03a0c05dba4c5f6a23c391f96de1614a098c","basis":"first unaffected version stated in the CVE record"},{"source":"CVE List","source_url":"https://www.cve.org/CVERecord?id=CVE-2026-98983","source_modified_at":"2026-10-23T12:20:00.918Z","fetched_at":"2026-10-23T18:42:43.628194Z","package":{"name":"Linux","ecosystem":null},"version":"0b6f31a3c0b16066f812e94b52a704174a6f23cd","basis":"first unaffected version stated in the CVE record"},{"source":"CVE List","source_url":"https://www.cve.org/CVERecord?id=CVE-2026-98983","source_modified_at":"2026-10-23T12:20:00.918Z","fetched_at":"2026-10-23T18:42:43.628194Z","package":{"name":"Linux","ecosystem":null},"version":"5.16","basis":"first unaffected version stated in the CVE record"},{"source":"CVE List","source_url":"https://www.cve.org/CVERecord?id=CVE-2026-98983","source_modified_at":"2026-10-23T12:20:00.918Z","fetched_at":"2026-10-23T18:42:43.628194Z","package":{"name":"Linux","ecosystem":null},"version":"6.2","basis":"first unaffected version stated in the CVE record"},{"source":"CVE List","source_url":"https://www.cve.org/CVERecord?id=CVE-2026-98983","source_modified_at":"2026-10-23T12:20:00.918Z","fetched_at":"2026-10-23T18:42:43.628194Z","package":{"name":"Linux","ecosystem":null},"version":"6.7","basis":"first unaffected version stated in the CVE record"},{"source":"CVE List","source_url":"https://www.cve.org/CVERecord?id=CVE-2026-98983","source_modified_at":"2026-10-23T12:20:00.918Z","fetched_at":"2026-10-23T18:42:43.628194Z","package":{"name":"Linux","ecosystem":null},"version":"6.13","basis":"first unaffected version stated in the CVE record"},{"source":"CVE List","source_url":"https://www.cve.org/CVERecord?id=CVE-2026-98983","source_modified_at":"2026-10-23T12:20:00.918Z","fetched_at":"2026-10-23T18:42:43.628194Z","package":{"name":"Linux","ecosystem":null},"version":"6.19","basis":"first unaffected version stated in the CVE record"},{"source":"CVE List","source_url":"https://www.cve.org/CVERecord?id=CVE-2026-98983","source_modified_at":"2026-10-23T12:20:00.918Z","fetched_at":"2026-10-23T18:42:43.628194Z","package":{"name":"Linux","ecosystem":null},"version":"7.1","basis":"first unaffected version stated in the CVE record"}],"cvss":null,"severity":null,"kev":{"listed":false},"epss":{"probability":null,"percentile":null,"score_date":null},"published_at":"2026-10-23T12:20:00.918Z","modified_at":"2026-10-23T12:20:00.918Z","provenance":[{"source":"CVE List","url":"https://www.cve.org/CVERecord?id=CVE-2026-98983","fetched_at":"2026-10-23T18:42:43.628194Z","source_modified_at":"2026-10-23T12:20:00.918Z"}],"sources":["CVE List"],"references":[{"source":"CVE List","url":"https://git.kernel.org/stable/c/56fe03a0c05dba4c5f6a23c391f96de1614a098c"},{"source":"CVE List","url":"https://git.kernel.org/stable/c/0b6f31a3c0b16066f812e94b52a704174a6f23cd"}],"locations":[],"motoko_assessment":{"status":"requires_architecture_review","automatic_remediation":false},"cve_state":"PUBLISHED","classification":{"method":"product-first software-layer rules","rules_version":"2.1","matched_on":"product","confidence":"heuristic","reviewed":false},"change_timestamp":"2026-10-23T12:20:00.918Z","content_hash":"29f7419ec2218b6f247382038cc3b3091d806a9af4e56ea58d2e413c89e477c2"}}