{"id":"CVE-2026-93288","state":"PUBLISHED","title":"netfilter: nfnetlink_log: wait for rcu grace period before freeing pernet state","description":"In the Linux kernel, the following vulnerability has been resolved:\n\nnetfilter: nfnetlink_log: wait for rcu grace period before freeing pernet state\n\nsashiko reports: \"nfnl_log_net_exit() calls nf_log_unset(), which\nclears the logger pointer without an RCU grace period.  Immediately after,\nops_free_list() frees the per-net state while concurrent packets might\nstill be executing nf_log_packet() under rcu_read_lock().\"\n\nClear the pointer via .pre_exit to make sure rcu readers have completed\nbefore pernet storage is free'd.  The change in nf_log_syslog.c is only\ndone for consistency: it doesn't use pernet data.","publishedAt":"2026-09-24T16:02:12.144Z","updatedAt":"2026-10-03T10:57:14.695Z","severity":{"score":7.8,"label":"High","version":"3.1","vector":"CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H","source":"Linux"},"assigner":"Linux","products":["Linux Linux"],"affected":[{"vendor":"Linux","product":"Linux","defaultStatus":"unaffected","versions":[{"version":"c83fa19603bdaeef17b815713dbbe3230c8a34ee","status":"affected","lessThan":"ba2e246aa294f9acd86194ea87fb6834ed0a37ac","versionType":"git"},{"version":"c83fa19603bdaeef17b815713dbbe3230c8a34ee","status":"affected","lessThan":"5570d6c8b320dbcc602617ee08c27ce752fed65a","versionType":"git"},{"version":"c83fa19603bdaeef17b815713dbbe3230c8a34ee","status":"affected","lessThan":"3b9aa62d78ce80de47af2db472ff452398755213","versionType":"git"},{"version":"c83fa19603bdaeef17b815713dbbe3230c8a34ee","status":"affected","lessThan":"f4461654374576e9d5d0245fd534c46ad8509051","versionType":"git"},{"version":"c83fa19603bdaeef17b815713dbbe3230c8a34ee","status":"affected","lessThan":"dc20050b6b12ca58066715d088e1a537535d938d","versionType":"git"},{"version":"c83fa19603bdaeef17b815713dbbe3230c8a34ee","status":"affected","lessThan":"33d1469b0124cc0baaea7a2032123b77a81e0940","versionType":"git"}],"repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","programFiles":["net/netfilter/nf_log_syslog.c","net/netfilter/nfnetlink_log.c"]},{"vendor":"Linux","product":"Linux","defaultStatus":"affected","versions":[{"version":"4.12","status":"affected"},{"version":"0","status":"unaffected","lessThan":"4.12","versionType":"semver"},{"version":"5.15.222","status":"unaffected","lessThanOrEqual":"5.15.*","versionType":"semver"},{"version":"6.1.189","status":"unaffected","lessThanOrEqual":"6.1.*","versionType":"semver"},{"version":"6.6.158","status":"unaffected","lessThanOrEqual":"6.6.*","versionType":"semver"},{"version":"6.12.111","status":"unaffected","lessThanOrEqual":"6.12.*","versionType":"semver"},{"version":"6.18.53","status":"unaffected","lessThanOrEqual":"6.18.*","versionType":"semver"},{"version":"7.2","status":"unaffected","lessThanOrEqual":"*","versionType":"original_commit_for_fix"}],"repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","programFiles":["net/netfilter/nf_log_syslog.c","net/netfilter/nfnetlink_log.c"]}],"references":["https://git.kernel.org/stable/c/ba2e246aa294f9acd86194ea87fb6834ed0a37ac","https://git.kernel.org/stable/c/5570d6c8b320dbcc602617ee08c27ce752fed65a","https://git.kernel.org/stable/c/3b9aa62d78ce80de47af2db472ff452398755213","https://git.kernel.org/stable/c/f4461654374576e9d5d0245fd534c46ad8509051","https://git.kernel.org/stable/c/dc20050b6b12ca58066715d088e1a537535d938d","https://git.kernel.org/stable/c/33d1469b0124cc0baaea7a2032123b77a81e0940"],"weaknesses":[],"ingestedAt":"2026-10-29T20:13:34.582Z","source":{"repository":"CVEProject/cvelistV5","path":"cves/2026/93xxx/CVE-2026-93288.json","commit":"556c9d3a8cd17e218bb8e452ba7cd619a384ff47"},"raw":{"dataType":"CVE_RECORD","dataVersion":"5.2","cveMetadata":{"cveId":"CVE-2026-93288","state":"PUBLISHED","datePublished":"2026-09-24T16:02:12.144Z","dateUpdated":"2026-10-03T10:57:14.695Z","assignerShortName":"Linux","assignerOrgId":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","dateReserved":"2026-09-17T16:02:15.099Z"},"containers":{"cna":{"title":"netfilter: nfnetlink_log: wait for rcu grace period before freeing pernet state","descriptions":[{"lang":"en","value":"In the Linux kernel, the following vulnerability has been resolved:\n\nnetfilter: nfnetlink_log: wait for rcu grace period before freeing pernet state\n\nsashiko reports: \"nfnl_log_net_exit() calls nf_log_unset(), which\nclears the logger pointer without an RCU grace period.  Immediately after,\nops_free_list() frees the per-net state while concurrent packets might\nstill be executing nf_log_packet() under rcu_read_lock().\"\n\nClear the pointer via .pre_exit to make sure rcu readers have completed\nbefore pernet storage is free'd.  The change in nf_log_syslog.c is only\ndone for consistency: it doesn't use pernet data."}],"affected":[{"vendor":"Linux","product":"Linux","defaultStatus":"unaffected","versions":[{"version":"c83fa19603bdaeef17b815713dbbe3230c8a34ee","status":"affected","lessThan":"ba2e246aa294f9acd86194ea87fb6834ed0a37ac","versionType":"git"},{"version":"c83fa19603bdaeef17b815713dbbe3230c8a34ee","status":"affected","lessThan":"5570d6c8b320dbcc602617ee08c27ce752fed65a","versionType":"git"},{"version":"c83fa19603bdaeef17b815713dbbe3230c8a34ee","status":"affected","lessThan":"3b9aa62d78ce80de47af2db472ff452398755213","versionType":"git"},{"version":"c83fa19603bdaeef17b815713dbbe3230c8a34ee","status":"affected","lessThan":"f4461654374576e9d5d0245fd534c46ad8509051","versionType":"git"},{"version":"c83fa19603bdaeef17b815713dbbe3230c8a34ee","status":"affected","lessThan":"dc20050b6b12ca58066715d088e1a537535d938d","versionType":"git"},{"version":"c83fa19603bdaeef17b815713dbbe3230c8a34ee","status":"affected","lessThan":"33d1469b0124cc0baaea7a2032123b77a81e0940","versionType":"git"}],"repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","programFiles":["net/netfilter/nf_log_syslog.c","net/netfilter/nfnetlink_log.c"]},{"vendor":"Linux","product":"Linux","defaultStatus":"affected","versions":[{"version":"4.12","status":"affected"},{"version":"0","status":"unaffected","lessThan":"4.12","versionType":"semver"},{"version":"5.15.222","status":"unaffected","lessThanOrEqual":"5.15.*","versionType":"semver"},{"version":"6.1.189","status":"unaffected","lessThanOrEqual":"6.1.*","versionType":"semver"},{"version":"6.6.158","status":"unaffected","lessThanOrEqual":"6.6.*","versionType":"semver"},{"version":"6.12.111","status":"unaffected","lessThanOrEqual":"6.12.*","versionType":"semver"},{"version":"6.18.53","status":"unaffected","lessThanOrEqual":"6.18.*","versionType":"semver"},{"version":"7.2","status":"unaffected","lessThanOrEqual":"*","versionType":"original_commit_for_fix"}],"repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","programFiles":["net/netfilter/nf_log_syslog.c","net/netfilter/nfnetlink_log.c"]}],"references":[{"url":"https://git.kernel.org/stable/c/ba2e246aa294f9acd86194ea87fb6834ed0a37ac"},{"url":"https://git.kernel.org/stable/c/5570d6c8b320dbcc602617ee08c27ce752fed65a"},{"url":"https://git.kernel.org/stable/c/3b9aa62d78ce80de47af2db472ff452398755213"},{"url":"https://git.kernel.org/stable/c/f4461654374576e9d5d0245fd534c46ad8509051"},{"url":"https://git.kernel.org/stable/c/dc20050b6b12ca58066715d088e1a537535d938d"},{"url":"https://git.kernel.org/stable/c/33d1469b0124cc0baaea7a2032123b77a81e0940"}],"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 UAF is in nfnl_log_net_exit() (unset moved to nfnl_log_net_pre_exit): cleanup_net() frees nfnl_log_net via ops_free_list() while nf_log_packet()→nfulnl_log_packet() still uses nfnl_log_pernet(). Setup is local NETLINK_NETFILTER nfulnl_recv_config (NFULNL_CFG_CMD_PF_BIND); no remote protocol message carries the bug.\nAC:L - The attacker PF_BINDs nfulnl_logger through nfulnl_recv_config, generates packets that enter nf_log_packet() (conntrack nf_l4proto_log_invalid() while those hooks still exist, or NFLOG), and drops the netns so cleanup_net() races nfnl_log_net_exit()/ops_free_list() against that reader; both sides are attacker-controlled.\nPR:L - nfnetlink_rcv() requires CAP_NET_ADMIN via netlink_net_capable() in sock_net(skb->sk)->user_ns before nfulnl_recv_config can bind the logger; an unprivileged user obtains that capability in a user+net namespace (unshare -Urn).\nUI:N - The attacker issues nfulnl_recv_config, injects the logged packets, and destroys their own netns; no victim mount, file open, or other interaction is required.\nS:U - The slab UAF of struct nfnl_log_net inside nfulnl_log_packet()/instance_lookup_get_rcu() is host-kernel memory corruption in the same kernel authority, not a VM escape or IOMMU/DMA bypass.\nC:H - After ops_free_list() kfree()s the per-net object, nfulnl_log_packet() still calls nfnl_log_pernet() and instance_lookup_get_rcu() walks the freed instance_table hlist, a slab UAF that can be reclaimed for arbitrary kernel reads.\nI:H - Use-after-free of nfnl_log_net's instance_table and the resulting nfulnl_instance pointer chase (hlist, inst->lock, inst->skb) is a heap UAF write primitive that can hijack control flow.\nA:H - instance_lookup_get_rcu()/nfulnl_log_packet() dereferencing the freed nfnl_log_net can oops or panic the kernel even when the UAF is not turned into a full exploit."}]}],"providerMetadata":{"shortName":"Linux","orgId":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","dateUpdated":"2026-10-03T10:57:14.695Z"},"cpeApplicability":[{"nodes":[{"operator":"OR","negate":false,"cpeMatch":[{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"4.12","versionEndExcluding":"5.15.222"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"4.12","versionEndExcluding":"6.1.189"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"4.12","versionEndExcluding":"6.6.158"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"4.12","versionEndExcluding":"6.12.111"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"4.12","versionEndExcluding":"6.18.53"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"4.12","versionEndExcluding":"7.2"}]}]}],"x_generator":{"engine":"bippy-1.2.0"}}}}}