{"api_version":"1","generated_at":"2026-05-06T11:59:35+00:00","cve":"CVE-2026-43116","urls":{"html":"https://cve.report/CVE-2026-43116","api":"https://cve.report/api/cve/CVE-2026-43116.json","docs":"https://cve.report/api","cve_org":"https://www.cve.org/CVERecord?id=CVE-2026-43116","nvd":"https://nvd.nist.gov/vuln/detail/CVE-2026-43116"},"summary":{"title":"netfilter: ctnetlink: ensure safe access to master conntrack","description":"In the Linux kernel, the following vulnerability has been resolved:\n\nnetfilter: ctnetlink: ensure safe access to master conntrack\n\nHolding reference on the expectation is not sufficient, the master\nconntrack object can just go away, making exp->master invalid.\n\nTo access exp->master safely:\n\n- Grab the nf_conntrack_expect_lock, this gets serialized with\n  clean_from_lists() which also holds this lock when the master\n  conntrack goes away.\n\n- Hold reference on master conntrack via nf_conntrack_find_get().\n  Not so easy since the master tuple to look up for the master conntrack\n  is not available in the existing problematic paths.\n\nThis patch goes for extending the nf_conntrack_expect_lock section\nto address this issue for simplicity, in the cases that are described\nbelow this is just slightly extending the lock section.\n\nThe add expectation command already holds a reference to the master\nconntrack from ctnetlink_create_expect().\n\nHowever, the delete expectation command needs to grab the spinlock\nbefore looking up for the expectation. Expand the existing spinlock\nsection to address this to cover the expectation lookup. Note that,\nthe nf_ct_expect_iterate_net() calls already grabs the spinlock while\niterating over the expectation table, which is correct.\n\nThe get expectation command needs to grab the spinlock to ensure master\nconntrack does not go away. This also expands the existing spinlock\nsection to cover the expectation lookup too. I needed to move the\nnetlink skb allocation out of the spinlock to keep it GFP_KERNEL.\n\nFor the expectation events, the IPEXP_DESTROY event is already delivered\nunder the spinlock, just move the delivery of IPEXP_NEW under the\nspinlock too because the master conntrack event cache is reached through\nexp->master.\n\nWhile at it, add lockdep notations to help identify what codepaths need\nto grab the spinlock.","state":"PUBLISHED","assigner":"Linux","published_at":"2026-05-06 10:16:25","updated_at":"2026-05-06 10:16:25"},"problem_types":[],"metrics":[],"references":[{"url":"https://git.kernel.org/stable/c/497f99b26fffdc5635706d1b4811f1ed8ee21a5b","name":"https://git.kernel.org/stable/c/497f99b26fffdc5635706d1b4811f1ed8ee21a5b","refsource":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","tags":[],"title":"","mime":"","httpstatus":"","archivestatus":"0"},{"url":"https://git.kernel.org/stable/c/bffcaad9afdfe45d7fc777397d3b83c1e3ebffe5","name":"https://git.kernel.org/stable/c/bffcaad9afdfe45d7fc777397d3b83c1e3ebffe5","refsource":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","tags":[],"title":"","mime":"","httpstatus":"","archivestatus":"0"},{"url":"https://git.kernel.org/stable/c/f338ced0473849c9f6ed0b77ca99f1aab5826787","name":"https://git.kernel.org/stable/c/f338ced0473849c9f6ed0b77ca99f1aab5826787","refsource":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","tags":[],"title":"","mime":"","httpstatus":"","archivestatus":"0"},{"url":"https://www.cve.org/CVERecord?id=CVE-2026-43116","name":"CVE Program record","refsource":"CVE.ORG","tags":["canonical"]},{"url":"https://nvd.nist.gov/vuln/detail/CVE-2026-43116","name":"NVD vulnerability detail","refsource":"NVD","tags":["canonical","analysis"]}],"affected":[{"source":"CNA","vendor":"Linux","product":"Linux","version":"affected 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 f338ced0473849c9f6ed0b77ca99f1aab5826787 git","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"affected 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 497f99b26fffdc5635706d1b4811f1ed8ee21a5b git","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"affected 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 bffcaad9afdfe45d7fc777397d3b83c1e3ebffe5 git","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"unaffected 6.18.24 6.18.* semver","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"unaffected 6.19.14 6.19.* semver","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"unaffected 7.0 * original_commit_for_fix","platforms":[]}],"timeline":[],"solutions":[],"workarounds":[],"exploits":[],"credits":[],"nvd_cpes":[],"vendor_comments":[],"enrichments":{"kev":null,"epss":null,"legacy_qids":[]},"source_records":{"cve_program":{"containers":{"cna":{"affected":[{"defaultStatus":"unaffected","product":"Linux","programFiles":["include/net/netfilter/nf_conntrack_core.h","net/netfilter/nf_conntrack_ecache.c","net/netfilter/nf_conntrack_expect.c","net/netfilter/nf_conntrack_netlink.c"],"repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","vendor":"Linux","versions":[{"lessThan":"f338ced0473849c9f6ed0b77ca99f1aab5826787","status":"affected","version":"1da177e4c3f41524e886b7f1b8a0c1fc7321cac2","versionType":"git"},{"lessThan":"497f99b26fffdc5635706d1b4811f1ed8ee21a5b","status":"affected","version":"1da177e4c3f41524e886b7f1b8a0c1fc7321cac2","versionType":"git"},{"lessThan":"bffcaad9afdfe45d7fc777397d3b83c1e3ebffe5","status":"affected","version":"1da177e4c3f41524e886b7f1b8a0c1fc7321cac2","versionType":"git"}]},{"defaultStatus":"affected","product":"Linux","programFiles":["include/net/netfilter/nf_conntrack_core.h","net/netfilter/nf_conntrack_ecache.c","net/netfilter/nf_conntrack_expect.c","net/netfilter/nf_conntrack_netlink.c"],"repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","vendor":"Linux","versions":[{"lessThanOrEqual":"6.18.*","status":"unaffected","version":"6.18.24","versionType":"semver"},{"lessThanOrEqual":"6.19.*","status":"unaffected","version":"6.19.14","versionType":"semver"},{"lessThanOrEqual":"*","status":"unaffected","version":"7.0","versionType":"original_commit_for_fix"}]}],"cpeApplicability":[{"nodes":[{"cpeMatch":[{"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionEndExcluding":"6.18.24","vulnerable":true},{"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionEndExcluding":"6.19.14","vulnerable":true},{"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionEndExcluding":"7.0","vulnerable":true}],"negate":false,"operator":"OR"}]}],"descriptions":[{"lang":"en","value":"In the Linux kernel, the following vulnerability has been resolved:\n\nnetfilter: ctnetlink: ensure safe access to master conntrack\n\nHolding reference on the expectation is not sufficient, the master\nconntrack object can just go away, making exp->master invalid.\n\nTo access exp->master safely:\n\n- Grab the nf_conntrack_expect_lock, this gets serialized with\n  clean_from_lists() which also holds this lock when the master\n  conntrack goes away.\n\n- Hold reference on master conntrack via nf_conntrack_find_get().\n  Not so easy since the master tuple to look up for the master conntrack\n  is not available in the existing problematic paths.\n\nThis patch goes for extending the nf_conntrack_expect_lock section\nto address this issue for simplicity, in the cases that are described\nbelow this is just slightly extending the lock section.\n\nThe add expectation command already holds a reference to the master\nconntrack from ctnetlink_create_expect().\n\nHowever, the delete expectation command needs to grab the spinlock\nbefore looking up for the expectation. Expand the existing spinlock\nsection to address this to cover the expectation lookup. Note that,\nthe nf_ct_expect_iterate_net() calls already grabs the spinlock while\niterating over the expectation table, which is correct.\n\nThe get expectation command needs to grab the spinlock to ensure master\nconntrack does not go away. This also expands the existing spinlock\nsection to cover the expectation lookup too. I needed to move the\nnetlink skb allocation out of the spinlock to keep it GFP_KERNEL.\n\nFor the expectation events, the IPEXP_DESTROY event is already delivered\nunder the spinlock, just move the delivery of IPEXP_NEW under the\nspinlock too because the master conntrack event cache is reached through\nexp->master.\n\nWhile at it, add lockdep notations to help identify what codepaths need\nto grab the spinlock."}],"providerMetadata":{"dateUpdated":"2026-05-06T07:40:41.185Z","orgId":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","shortName":"Linux"},"references":[{"url":"https://git.kernel.org/stable/c/f338ced0473849c9f6ed0b77ca99f1aab5826787"},{"url":"https://git.kernel.org/stable/c/497f99b26fffdc5635706d1b4811f1ed8ee21a5b"},{"url":"https://git.kernel.org/stable/c/bffcaad9afdfe45d7fc777397d3b83c1e3ebffe5"}],"title":"netfilter: ctnetlink: ensure safe access to master conntrack","x_generator":{"engine":"bippy-1.2.0"}}},"cveMetadata":{"assignerOrgId":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","assignerShortName":"Linux","cveId":"CVE-2026-43116","datePublished":"2026-05-06T07:40:41.185Z","dateReserved":"2026-05-01T14:12:55.986Z","dateUpdated":"2026-05-06T07:40:41.185Z","state":"PUBLISHED"},"dataType":"CVE_RECORD","dataVersion":"5.2"},"nvd":{"publishedDate":"2026-05-06 10:16:25","lastModifiedDate":"2026-05-06 10:16:25","problem_types":[],"metrics":[],"configurations":[]},"legacy_mitre":{"record":{"CveYear":"2026","CveId":"43116","Ordinal":"1","Title":"netfilter: ctnetlink: ensure safe access to master conntrack","CVE":"CVE-2026-43116","Year":"2026"},"notes":[{"CveYear":"2026","CveId":"43116","Ordinal":"1","NoteData":"In the Linux kernel, the following vulnerability has been resolved:\n\nnetfilter: ctnetlink: ensure safe access to master conntrack\n\nHolding reference on the expectation is not sufficient, the master\nconntrack object can just go away, making exp->master invalid.\n\nTo access exp->master safely:\n\n- Grab the nf_conntrack_expect_lock, this gets serialized with\n  clean_from_lists() which also holds this lock when the master\n  conntrack goes away.\n\n- Hold reference on master conntrack via nf_conntrack_find_get().\n  Not so easy since the master tuple to look up for the master conntrack\n  is not available in the existing problematic paths.\n\nThis patch goes for extending the nf_conntrack_expect_lock section\nto address this issue for simplicity, in the cases that are described\nbelow this is just slightly extending the lock section.\n\nThe add expectation command already holds a reference to the master\nconntrack from ctnetlink_create_expect().\n\nHowever, the delete expectation command needs to grab the spinlock\nbefore looking up for the expectation. Expand the existing spinlock\nsection to address this to cover the expectation lookup. Note that,\nthe nf_ct_expect_iterate_net() calls already grabs the spinlock while\niterating over the expectation table, which is correct.\n\nThe get expectation command needs to grab the spinlock to ensure master\nconntrack does not go away. This also expands the existing spinlock\nsection to cover the expectation lookup too. I needed to move the\nnetlink skb allocation out of the spinlock to keep it GFP_KERNEL.\n\nFor the expectation events, the IPEXP_DESTROY event is already delivered\nunder the spinlock, just move the delivery of IPEXP_NEW under the\nspinlock too because the master conntrack event cache is reached through\nexp->master.\n\nWhile at it, add lockdep notations to help identify what codepaths need\nto grab the spinlock.","Type":"Description","Title":"netfilter: ctnetlink: ensure safe access to master conntrack"}]}}}