{ "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" } } } }