CVE-2026-74569 (GCVE-0-2026-74569)
Vulnerability from cvelistv5
Published
2026-08-15 12:28
Modified
2026-08-19 16:39
Severity ?
VLAI Severity ?
EPSS score ?
Summary
In the Linux kernel, the following vulnerability has been resolved:
netfilter: nf_conntrack_sip: widen NAT rewrite delta to s32 in sip_help_tcp()
sip_help_tcp() stores the size change of each NAT-rewritten SIP message
in s16 diff and accumulates it in s16 tdiff, but a single message can
grow by more than S16_MAX while the packet stays under the 65535
enlarge_skb() limit: nf_nat_sip() rewrites every matching URI, and a long
Contact list expands the message by tens of kilobytes. diff then wraps,
and "datalen = datalen + diff - msglen" yields a huge unsigned datalen,
so the next iteration's ct_sip_get_header() reads past the linearized skb
tail.
Widen diff, tdiff and the seq_adjust hook to s32. Both are bounded by the
65535 byte packet limit, and the seqadj core is already s32
(nf_ct_seqadj_set() takes s32), so no previously accepted input is
rejected.
BUG: KASAN: use-after-free in ct_sip_get_header (net/netfilter/nf_conntrack_sip.c:464)
Read of size 1 at addr ffff888010800000 by task ksoftirqd/1/25
ct_sip_get_header (net/netfilter/nf_conntrack_sip.c:464)
sip_help_tcp (net/netfilter/nf_conntrack_sip.c:1694)
nf_confirm (net/netfilter/nf_conntrack_proto.c:183)
nf_hook_slow (net/netfilter/core.c:619)
ip6_output (net/ipv6/ip6_output.c:246)
ip6_forward (net/ipv6/ip6_output.c:690)
ipv6_rcv (net/ipv6/ip6_input.c:351)
__netif_receive_skb_one_core (net/core/dev.c:6212)
process_backlog (net/core/dev.c:6676)
__napi_poll (net/core/dev.c:7735)
net_rx_action (net/core/dev.c:7955)
handle_softirqs (kernel/softirq.c:622)
run_ksoftirqd (kernel/softirq.c:1076)
...
References
Impacted products
| Vendor | Product | Version | ||
|---|---|---|---|---|
| Linux | Linux |
Version: f5b321bd37fbec9188feb1f721ab46a5ac0b35da Version: f5b321bd37fbec9188feb1f721ab46a5ac0b35da Version: f5b321bd37fbec9188feb1f721ab46a5ac0b35da Version: f5b321bd37fbec9188feb1f721ab46a5ac0b35da Version: f5b321bd37fbec9188feb1f721ab46a5ac0b35da Version: f5b321bd37fbec9188feb1f721ab46a5ac0b35da Version: f5b321bd37fbec9188feb1f721ab46a5ac0b35da Version: f5b321bd37fbec9188feb1f721ab46a5ac0b35da |
||
{
"containers": {
"cna": {
"affected": [
{
"defaultStatus": "unaffected",
"product": "Linux",
"programFiles": [
"include/linux/netfilter/nf_conntrack_sip.h",
"net/netfilter/nf_conntrack_sip.c",
"net/netfilter/nf_nat_sip.c"
],
"repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
"vendor": "Linux",
"versions": [
{
"lessThan": "ed1f9be6dc8e2e280b8725e44ccdc6e0cd38640d",
"status": "affected",
"version": "f5b321bd37fbec9188feb1f721ab46a5ac0b35da",
"versionType": "git"
},
{
"lessThan": "1b0843f9e9b9b0b9b4b70d143b67e58163c85b2c",
"status": "affected",
"version": "f5b321bd37fbec9188feb1f721ab46a5ac0b35da",
"versionType": "git"
},
{
"lessThan": "32d4abc8923b0d4046fd63ad6e4917872e44eb6d",
"status": "affected",
"version": "f5b321bd37fbec9188feb1f721ab46a5ac0b35da",
"versionType": "git"
},
{
"lessThan": "63eea41759fd682229c14e0a2205802b46d106f3",
"status": "affected",
"version": "f5b321bd37fbec9188feb1f721ab46a5ac0b35da",
"versionType": "git"
},
{
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"status": "affected",
"version": "f5b321bd37fbec9188feb1f721ab46a5ac0b35da",
"versionType": "git"
},
{
"lessThan": "f74554e67ccf04d1fa71069e8c9afa2717e40716",
"status": "affected",
"version": "f5b321bd37fbec9188feb1f721ab46a5ac0b35da",
"versionType": "git"
},
{
"lessThan": "ef5e2c6555d2bb52dfe0e4053a8c6193f9d83b64",
"status": "affected",
"version": "f5b321bd37fbec9188feb1f721ab46a5ac0b35da",
"versionType": "git"
},
{
"lessThan": "db3d0e0e5d4bc5ab4fe445b9f413d1b486508ca5",
"status": "affected",
"version": "f5b321bd37fbec9188feb1f721ab46a5ac0b35da",
"versionType": "git"
}
]
},
{
"defaultStatus": "affected",
"product": "Linux",
"programFiles": [
"include/linux/netfilter/nf_conntrack_sip.h",
"net/netfilter/nf_conntrack_sip.c",
"net/netfilter/nf_nat_sip.c"
],
"repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
"vendor": "Linux",
"versions": [
{
"status": "affected",
"version": "2.6.34"
},
{
"lessThan": "2.6.34",
"status": "unaffected",
"version": "0",
"versionType": "semver"
},
{
"lessThanOrEqual": "5.10.*",
"status": "unaffected",
"version": "5.10.265",
"versionType": "semver"
},
{
"lessThanOrEqual": "5.15.*",
"status": "unaffected",
"version": "5.15.216",
"versionType": "semver"
},
{
"lessThanOrEqual": "6.1.*",
"status": "unaffected",
"version": "6.1.183",
"versionType": "semver"
},
{
"lessThanOrEqual": "6.6.*",
"status": "unaffected",
"version": "6.6.151",
"versionType": "semver"
},
{
"lessThanOrEqual": "6.12.*",
"status": "unaffected",
"version": "6.12.103",
"versionType": "semver"
},
{
"lessThanOrEqual": "6.18.*",
"status": "unaffected",
"version": "6.18.44",
"versionType": "semver"
},
{
"lessThanOrEqual": "7.1.*",
"status": "unaffected",
"version": "7.1.8",
"versionType": "semver"
},
{
"lessThanOrEqual": "*",
"status": "unaffected",
"version": "7.2",
"versionType": "original_commit_for_fix"
}
]
}
],
"cpeApplicability": [
{
"nodes": [
{
"cpeMatch": [
{
"criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
"versionEndExcluding": "5.10.265",
"versionStartIncluding": "2.6.34",
"vulnerable": true
},
{
"criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
"versionEndExcluding": "5.15.216",
"versionStartIncluding": "2.6.34",
"vulnerable": true
},
{
"criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
"versionEndExcluding": "6.1.183",
"versionStartIncluding": "2.6.34",
"vulnerable": true
},
{
"criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
"versionEndExcluding": "6.6.151",
"versionStartIncluding": "2.6.34",
"vulnerable": true
},
{
"criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
"versionEndExcluding": "6.12.103",
"versionStartIncluding": "2.6.34",
"vulnerable": true
},
{
"criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
"versionEndExcluding": "6.18.44",
"versionStartIncluding": "2.6.34",
"vulnerable": true
},
{
"criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
"versionEndExcluding": "7.1.8",
"versionStartIncluding": "2.6.34",
"vulnerable": true
},
{
"criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
"versionEndExcluding": "7.2",
"versionStartIncluding": "2.6.34",
"vulnerable": true
}
],
"negate": false,
"operator": "OR"
}
]
}
],
"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\u0027s 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": {
"baseScore": 9.8,
"baseSeverity": "CRITICAL",
"vectorString": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H",
"version": "3.1"
},
"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\u2192ip6_forward\u2192ip6_output\u2192nf_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 \u003e32KB 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."
}
]
}
],
"providerMetadata": {
"dateUpdated": "2026-08-19T16:39:11.673Z",
"orgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
"shortName": "Linux"
},
"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"
}
}
},
"cveMetadata": {
"assignerOrgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
"assignerShortName": "Linux",
"cveId": "CVE-2026-74569",
"datePublished": "2026-08-15T12:28:09.476Z",
"dateReserved": "2026-08-15T05:44:03.917Z",
"dateUpdated": "2026-08-19T16:39:11.673Z",
"state": "PUBLISHED"
},
"dataType": "CVE_RECORD",
"dataVersion": "5.2"
}
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Sightings
| Author | Source | Type | Date |
|---|
Nomenclature
- Seen: The vulnerability was mentioned, discussed, or seen somewhere by the user.
- Confirmed: The vulnerability is confirmed from an analyst perspective.
- Published Proof of Concept: A public proof of concept is available for this vulnerability.
- Exploited: This vulnerability was exploited and seen by the user reporting the sighting.
- Patched: This vulnerability was successfully patched by the user reporting the sighting.
- Not exploited: This vulnerability was not exploited or seen by the user reporting the sighting.
- Not confirmed: The user expresses doubt about the veracity of the vulnerability.
- Not patched: This vulnerability was not successfully patched by the user reporting the sighting.
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