{"dataType":"CVE_RECORD","dataVersion":"5.2","cveMetadata":{"cveId":"CVE-2026-74569","assignerOrgId":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","state":"PUBLISHED","assignerShortName":"Linux","dateReserved":"2026-08-15T05:44:03.917Z","datePublished":"2026-08-15T12:28:09.476Z","dateUpdated":"2026-08-19T16:39:11.673Z"},"containers":{"cna":{"providerMetadata":{"orgId":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","shortName":"Linux","dateUpdated":"2026-08-19T16:39:11.673Z"},"descriptions":[{"lang":"en","value":"In the Linux kernel, the following vulnerability has been resolved:\n\nnetfilter: nf_conntrack_sip: widen NAT rewrite delta to s32 in sip_help_tcp()\n\nsip_help_tcp() stores the size change of each NAT-rewritten SIP message\nin s16 diff and accumulates it in s16 tdiff, but a single message can\ngrow by more than S16_MAX while the packet stays under the 65535\nenlarge_skb() limit: nf_nat_sip() rewrites every matching URI, and a long\nContact list expands the message by tens of kilobytes. diff then wraps,\nand \"datalen = datalen + diff - msglen\" yields a huge unsigned datalen,\nso the next iteration's ct_sip_get_header() reads past the linearized skb\ntail.\n\nWiden diff, tdiff and the seq_adjust hook to s32. Both are bounded by the\n65535 byte packet limit, and the seqadj core is already s32\n(nf_ct_seqadj_set() takes s32), so no previously accepted input is\nrejected.\n\n  BUG: KASAN: use-after-free in ct_sip_get_header (net/netfilter/nf_conntrack_sip.c:464)\n  Read of size 1 at addr ffff888010800000 by task ksoftirqd/1/25\n   ct_sip_get_header (net/netfilter/nf_conntrack_sip.c:464)\n   sip_help_tcp (net/netfilter/nf_conntrack_sip.c:1694)\n   nf_confirm (net/netfilter/nf_conntrack_proto.c:183)\n   nf_hook_slow (net/netfilter/core.c:619)\n   ip6_output (net/ipv6/ip6_output.c:246)\n   ip6_forward (net/ipv6/ip6_output.c:690)\n   ipv6_rcv (net/ipv6/ip6_input.c:351)\n   __netif_receive_skb_one_core (net/core/dev.c:6212)\n   process_backlog (net/core/dev.c:6676)\n   __napi_poll (net/core/dev.c:7735)\n   net_rx_action (net/core/dev.c:7955)\n   handle_softirqs (kernel/softirq.c:622)\n   run_ksoftirqd (kernel/softirq.c:1076)\n   ..."}],"metrics":[{"cvssV3_1":{"version":"3.1","vectorString":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H","baseScore":9.8,"baseSeverity":"CRITICAL"},"scenarios":[{"lang":"en","value":"AV:N - Remote attackers trigger sip_help_tcp() by sending crafted TCP SIP traffic that traverses netfilter nf_confirm() on POST_ROUTING/LOCAL_IN during packet receive/forward (ipv6_rcv→ip6_forward→ip6_output→nf_hook_slow), the standard path for network-facing SIP ALG/NAT gateways.\nAC:L - Once nf_conntrack_sip and nf_nat_sip are active on a NATed SIP flow, the attacker fully controls the TCP SIP payload (Contact list length and private URIs) to force >32KB NAT expansion and deterministic s16 wrap; no race or external timing is required.\nPR:N - Exploitation requires no privileges on the victim kernel; a remote SIP peer only needs to deliver malicious TCP SIP packets through an already-configured SIP conntrack/NAT helper, with no authentication or local access to the target system.\nUI:N - No victim user interaction is required beyond normal automated packet processing; the helper parses and NAT-rewrites attacker-supplied SIP data in softirq during connection tracking confirmation without any user action.\nS:U - Impact is confined to kernel netfilter/conntrack memory on the same security authority (e.g., a NAT firewall or router). This is not a VM escape, sandbox breakout, or cross-tenant boundary violation.\nC:H - Integer overflow yields a huge unsigned datalen, causing ct_sip_get_header() to read past the linearized skb tail; KASAN reports a use-after-free read, and this out-of-bounds/UAF access can disclose adjacent kernel heap memory beyond the packet buffer.\nI:H - Although the immediate fault is a read past skb bounds, KASAN-classified UAF/out-of-bounds kernel heap corruption is exploitable with heap grooming for control of freed/reallocated objects, enabling arbitrary write and potential code execution in kernel context.\nA:H - The corrupted datalen drives out-of-bounds access in softirq packet processing (ksoftirqd), which can cause kernel oops/panic and denial of service on the NAT/firewall handling the SIP flow; the bug is reliably triggerable with crafted packets."}]}],"affected":[{"product":"Linux","vendor":"Linux","defaultStatus":"unaffected","repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","programFiles":["include/linux/netfilter/nf_conntrack_sip.h","net/netfilter/nf_conntrack_sip.c","net/netfilter/nf_nat_sip.c"],"versions":[{"version":"f5b321bd37fbec9188feb1f721ab46a5ac0b35da","lessThan":"ed1f9be6dc8e2e280b8725e44ccdc6e0cd38640d","status":"affected","versionType":"git"},{"version":"f5b321bd37fbec9188feb1f721ab46a5ac0b35da","lessThan":"1b0843f9e9b9b0b9b4b70d143b67e58163c85b2c","status":"affected","versionType":"git"},{"version":"f5b321bd37fbec9188feb1f721ab46a5ac0b35da","lessThan":"32d4abc8923b0d4046fd63ad6e4917872e44eb6d","status":"affected","versionType":"git"},{"version":"f5b321bd37fbec9188feb1f721ab46a5ac0b35da","lessThan":"63eea41759fd682229c14e0a2205802b46d106f3","status":"affected","versionType":"git"},{"version":"f5b321bd37fbec9188feb1f721ab46a5ac0b35da","lessThan":"c97621a110e386b2dd69e276eb699e1d3cec581d","status":"affected","versionType":"git"},{"version":"f5b321bd37fbec9188feb1f721ab46a5ac0b35da","lessThan":"f74554e67ccf04d1fa71069e8c9afa2717e40716","status":"affected","versionType":"git"},{"version":"f5b321bd37fbec9188feb1f721ab46a5ac0b35da","lessThan":"ef5e2c6555d2bb52dfe0e4053a8c6193f9d83b64","status":"affected","versionType":"git"},{"version":"f5b321bd37fbec9188feb1f721ab46a5ac0b35da","lessThan":"db3d0e0e5d4bc5ab4fe445b9f413d1b486508ca5","status":"affected","versionType":"git"}]},{"product":"Linux","vendor":"Linux","defaultStatus":"affected","repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","programFiles":["include/linux/netfilter/nf_conntrack_sip.h","net/netfilter/nf_conntrack_sip.c","net/netfilter/nf_nat_sip.c"],"versions":[{"version":"2.6.34","status":"affected"},{"version":"0","lessThan":"2.6.34","status":"unaffected","versionType":"semver"},{"version":"5.10.265","lessThanOrEqual":"5.10.*","status":"unaffected","versionType":"semver"},{"version":"5.15.216","lessThanOrEqual":"5.15.*","status":"unaffected","versionType":"semver"},{"version":"6.1.183","lessThanOrEqual":"6.1.*","status":"unaffected","versionType":"semver"},{"version":"6.6.151","lessThanOrEqual":"6.6.*","status":"unaffected","versionType":"semver"},{"version":"6.12.103","lessThanOrEqual":"6.12.*","status":"unaffected","versionType":"semver"},{"version":"6.18.44","lessThanOrEqual":"6.18.*","status":"unaffected","versionType":"semver"},{"version":"7.1.8","lessThanOrEqual":"7.1.*","status":"unaffected","versionType":"semver"},{"version":"7.2","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":"2.6.34","versionEndExcluding":"5.10.265"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"2.6.34","versionEndExcluding":"5.15.216"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"2.6.34","versionEndExcluding":"6.1.183"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"2.6.34","versionEndExcluding":"6.6.151"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"2.6.34","versionEndExcluding":"6.12.103"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"2.6.34","versionEndExcluding":"6.18.44"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"2.6.34","versionEndExcluding":"7.1.8"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"2.6.34","versionEndExcluding":"7.2"}]}]}],"references":[{"url":"https://git.kernel.org/stable/c/ed1f9be6dc8e2e280b8725e44ccdc6e0cd38640d"},{"url":"https://git.kernel.org/stable/c/1b0843f9e9b9b0b9b4b70d143b67e58163c85b2c"},{"url":"https://git.kernel.org/stable/c/32d4abc8923b0d4046fd63ad6e4917872e44eb6d"},{"url":"https://git.kernel.org/stable/c/63eea41759fd682229c14e0a2205802b46d106f3"},{"url":"https://git.kernel.org/stable/c/c97621a110e386b2dd69e276eb699e1d3cec581d"},{"url":"https://git.kernel.org/stable/c/f74554e67ccf04d1fa71069e8c9afa2717e40716"},{"url":"https://git.kernel.org/stable/c/ef5e2c6555d2bb52dfe0e4053a8c6193f9d83b64"},{"url":"https://git.kernel.org/stable/c/db3d0e0e5d4bc5ab4fe445b9f413d1b486508ca5"}],"title":"netfilter: nf_conntrack_sip: widen NAT rewrite delta to s32 in sip_help_tcp()","x_generator":{"engine":"bippy-1.2.0"}}}}