{"id":"CVE-2026-74624","state":"PUBLISHED","title":"netfilter: nf_conntrack: defer invalid log until after unlock","description":"In the Linux kernel, the following vulnerability has been resolved:\n\nnetfilter: nf_conntrack: defer invalid log until after unlock\n\nTCP and SCTP conntrack paths can emit invalid-packet logs while ct->lock\nis still held.\n\nWhen invalid logging is routed to nfnetlink_log and conntrack export is\nenabled, the log path can re-enter conntrack netlink glue and dump the\nsame conntrack again. Protocol attribute dumping may take ct->lock, so\nlogging while holding that lock can deadlock.\n\nDefer the TCP invalid logs by storing only the minimal log context while\nct->lock is held and emitting the log after unlocking. Also make the TCP\ntimeout-lowering invalid path return whether a log is needed, then emit\nthat log after unlocking.\n\nDo the same for the SCTP invalid state-transition log that can be reached\nwhile ct->lock is held.\n\nAdd a lockdep assertion to nf_ct_l4proto_log_invalid() so future callers\nthat log invalid conntracks while holding ct->lock are caught outside TCP\nand SCTP as well.","publishedAt":"2026-08-22T15:32:07.193Z","updatedAt":"2026-10-16T19:06:02.842Z","severity":{"score":7.5,"label":"High","version":"3.1","vector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H","source":"Linux"},"assigner":"Linux","products":["Linux Linux"],"affected":[{"vendor":"Linux","product":"Linux","defaultStatus":"unaffected","versions":[{"version":"d9a6f0d0df1899ff9086a57abc600e414f4b8cdd","status":"affected","lessThan":"ca97360eba4b3dc67f1804625542f4ccc774242a","versionType":"git"},{"version":"d9a6f0d0df1899ff9086a57abc600e414f4b8cdd","status":"affected","lessThan":"63853eb20bba4e00b7cd0b8cfc19337bbaaf5037","versionType":"git"},{"version":"d9a6f0d0df1899ff9086a57abc600e414f4b8cdd","status":"affected","lessThan":"9480fcf70a5aa9d320088a01c95df0e5e6391f4a","versionType":"git"},{"version":"d9a6f0d0df1899ff9086a57abc600e414f4b8cdd","status":"affected","lessThan":"0424186d570aa4d1ad17f516afb86bd9eaa4f42e","versionType":"git"},{"version":"d9a6f0d0df1899ff9086a57abc600e414f4b8cdd","status":"affected","lessThan":"c0224327b7cbed9d3198e8dbec847281053dcd06","versionType":"git"},{"version":"d9a6f0d0df1899ff9086a57abc600e414f4b8cdd","status":"affected","lessThan":"2d19b95c9723001f214f7a47d67b09f46238f200","versionType":"git"}],"repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","programFiles":["net/netfilter/nf_conntrack_proto.c","net/netfilter/nf_conntrack_proto_sctp.c","net/netfilter/nf_conntrack_proto_tcp.c"]},{"vendor":"Linux","product":"Linux","defaultStatus":"affected","versions":[{"version":"6.1","status":"affected"},{"version":"0","status":"unaffected","lessThan":"6.1","versionType":"semver"},{"version":"6.1.184","status":"unaffected","lessThanOrEqual":"6.1.*","versionType":"semver"},{"version":"6.6.152","status":"unaffected","lessThanOrEqual":"6.6.*","versionType":"semver"},{"version":"6.12.104","status":"unaffected","lessThanOrEqual":"6.12.*","versionType":"semver"},{"version":"6.18.45","status":"unaffected","lessThanOrEqual":"6.18.*","versionType":"semver"},{"version":"7.1.9","status":"unaffected","lessThanOrEqual":"7.1.*","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_conntrack_proto.c","net/netfilter/nf_conntrack_proto_sctp.c","net/netfilter/nf_conntrack_proto_tcp.c"]}],"references":["https://git.kernel.org/stable/c/ca97360eba4b3dc67f1804625542f4ccc774242a","https://git.kernel.org/stable/c/63853eb20bba4e00b7cd0b8cfc19337bbaaf5037","https://git.kernel.org/stable/c/9480fcf70a5aa9d320088a01c95df0e5e6391f4a","https://git.kernel.org/stable/c/0424186d570aa4d1ad17f516afb86bd9eaa4f42e","https://git.kernel.org/stable/c/c0224327b7cbed9d3198e8dbec847281053dcd06","https://git.kernel.org/stable/c/2d19b95c9723001f214f7a47d67b09f46238f200"],"weaknesses":[],"ingestedAt":"2026-10-29T20:12:58.252Z","source":{"repository":"CVEProject/cvelistV5","path":"cves/2026/74xxx/CVE-2026-74624.json","commit":"556c9d3a8cd17e218bb8e452ba7cd619a384ff47"},"raw":{"dataType":"CVE_RECORD","dataVersion":"5.2","cveMetadata":{"cveId":"CVE-2026-74624","state":"PUBLISHED","datePublished":"2026-08-22T15:32:07.193Z","dateUpdated":"2026-10-16T19:06:02.842Z","assignerShortName":"Linux","assignerOrgId":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","dateReserved":"2026-08-15T05:44:03.921Z"},"containers":{"cna":{"title":"netfilter: nf_conntrack: defer invalid log until after unlock","descriptions":[{"lang":"en","value":"In the Linux kernel, the following vulnerability has been resolved:\n\nnetfilter: nf_conntrack: defer invalid log until after unlock\n\nTCP and SCTP conntrack paths can emit invalid-packet logs while ct->lock\nis still held.\n\nWhen invalid logging is routed to nfnetlink_log and conntrack export is\nenabled, the log path can re-enter conntrack netlink glue and dump the\nsame conntrack again. Protocol attribute dumping may take ct->lock, so\nlogging while holding that lock can deadlock.\n\nDefer the TCP invalid logs by storing only the minimal log context while\nct->lock is held and emitting the log after unlocking. Also make the TCP\ntimeout-lowering invalid path return whether a log is needed, then emit\nthat log after unlocking.\n\nDo the same for the SCTP invalid state-transition log that can be reached\nwhile ct->lock is held.\n\nAdd a lockdep assertion to nf_ct_l4proto_log_invalid() so future callers\nthat log invalid conntracks while holding ct->lock are caught outside TCP\nand SCTP as well."}],"affected":[{"vendor":"Linux","product":"Linux","defaultStatus":"unaffected","versions":[{"version":"d9a6f0d0df1899ff9086a57abc600e414f4b8cdd","status":"affected","lessThan":"ca97360eba4b3dc67f1804625542f4ccc774242a","versionType":"git"},{"version":"d9a6f0d0df1899ff9086a57abc600e414f4b8cdd","status":"affected","lessThan":"63853eb20bba4e00b7cd0b8cfc19337bbaaf5037","versionType":"git"},{"version":"d9a6f0d0df1899ff9086a57abc600e414f4b8cdd","status":"affected","lessThan":"9480fcf70a5aa9d320088a01c95df0e5e6391f4a","versionType":"git"},{"version":"d9a6f0d0df1899ff9086a57abc600e414f4b8cdd","status":"affected","lessThan":"0424186d570aa4d1ad17f516afb86bd9eaa4f42e","versionType":"git"},{"version":"d9a6f0d0df1899ff9086a57abc600e414f4b8cdd","status":"affected","lessThan":"c0224327b7cbed9d3198e8dbec847281053dcd06","versionType":"git"},{"version":"d9a6f0d0df1899ff9086a57abc600e414f4b8cdd","status":"affected","lessThan":"2d19b95c9723001f214f7a47d67b09f46238f200","versionType":"git"}],"repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","programFiles":["net/netfilter/nf_conntrack_proto.c","net/netfilter/nf_conntrack_proto_sctp.c","net/netfilter/nf_conntrack_proto_tcp.c"]},{"vendor":"Linux","product":"Linux","defaultStatus":"affected","versions":[{"version":"6.1","status":"affected"},{"version":"0","status":"unaffected","lessThan":"6.1","versionType":"semver"},{"version":"6.1.184","status":"unaffected","lessThanOrEqual":"6.1.*","versionType":"semver"},{"version":"6.6.152","status":"unaffected","lessThanOrEqual":"6.6.*","versionType":"semver"},{"version":"6.12.104","status":"unaffected","lessThanOrEqual":"6.12.*","versionType":"semver"},{"version":"6.18.45","status":"unaffected","lessThanOrEqual":"6.18.*","versionType":"semver"},{"version":"7.1.9","status":"unaffected","lessThanOrEqual":"7.1.*","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_conntrack_proto.c","net/netfilter/nf_conntrack_proto_sctp.c","net/netfilter/nf_conntrack_proto_tcp.c"]}],"references":[{"url":"https://git.kernel.org/stable/c/ca97360eba4b3dc67f1804625542f4ccc774242a"},{"url":"https://git.kernel.org/stable/c/63853eb20bba4e00b7cd0b8cfc19337bbaaf5037"},{"url":"https://git.kernel.org/stable/c/9480fcf70a5aa9d320088a01c95df0e5e6391f4a"},{"url":"https://git.kernel.org/stable/c/0424186d570aa4d1ad17f516afb86bd9eaa4f42e"},{"url":"https://git.kernel.org/stable/c/c0224327b7cbed9d3198e8dbec847281053dcd06"},{"url":"https://git.kernel.org/stable/c/2d19b95c9723001f214f7a47d67b09f46238f200"}],"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 - The flaw is hit in nf_conntrack_tcp_packet()/nf_conntrack_sctp_packet() from the NF_INET_PRE_ROUTING and LOCAL_OUT netfilter hooks on received or forwarded TCP/SCTP traffic, so a remote peer can trigger invalid conntrack handling with crafted packets to internet-facing NAT gateways, routers, and servers.\nAC:L - Once nf_conntrack_log_invalid, nflog binding, and NFULNL_CFG_F_CONNTRACK are enabled (the CVE-scoped configuration on monitored firewalls), an attacker deterministically deadlocks by sending invalid-sequence TCP or invalid-state SCTP packets on tracked flows without races or special memory layout.\nPR:N - Triggering the vulnerable conntrack path requires only the ability to send TCP/SCTP packets to a host already running connection tracking with invalid logging; no local account, CAP_NET_ADMIN, or netlink configuration privileges are needed on the attacker side.\nUI:N - Exploitation is driven entirely by network packet delivery and softirq packet processing; no victim must open files, mount filesystems, or perform any interactive action beyond normal network connectivity to the target.\nS:U - The deadlock confines impact to the same kernel networking authority processing the packet; it does not cross VM, container, or IOMMU boundaries to compromise a separate security domain.\nC:N - This is a recursive spinlock deadlock in conntrack invalid logging with no memory corruption, out-of-bounds access, use-after-free, or information-disclosure primitive.\nI:N - The bug causes a lock re-entry hang during logging only; it does not modify kernel or user data, provide arbitrary write primitives, or enable code execution.\nA:H - Re-acquiring ct->lock while it is held deadlocks packet processing on the affected CPU in softirq context, can stall networking on that core, and may escalate to soft lockup or watchdog-induced kernel panic under sustained attack."}]}],"providerMetadata":{"shortName":"Linux","orgId":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","dateUpdated":"2026-08-25T05:40:47.114Z"},"cpeApplicability":[{"nodes":[{"operator":"OR","negate":false,"cpeMatch":[{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"6.1","versionEndExcluding":"6.1.184"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"6.1","versionEndExcluding":"6.6.152"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"6.1","versionEndExcluding":"6.12.104"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"6.1","versionEndExcluding":"6.18.45"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"6.1","versionEndExcluding":"7.1.9"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"6.1","versionEndExcluding":"7.2"}]}]}],"x_generator":{"engine":"bippy-1.2.0"}},"adp":[{"title":"CISA ADP Vulnrichment","metrics":[{"other":{"type":"ssvc","content":{"id":"CVE-2026-74624","role":"CISA Coordinator","options":[{"Exploitation":"none"},{"Automatable":"yes"},{"Technical Impact":"partial"}],"version":"2.0.3","timestamp":"2026-10-16T19:02:43.340591Z"}}}],"providerMetadata":{"shortName":"CISA-ADP","orgId":"134c704f-9b21-4f2e-91b3-4a467353bcc0","dateUpdated":"2026-10-16T19:06:02.842Z"}}]}}}