netfilter: nf_conntrack_sip: widen NAT rewrite delta to s32 in sip_help_tcp()

MITRE NVD CVE.ORG JSON API

Summary

CVECVE-2026-74569
StatePUBLISHED
AssignerLinux
Source PriorityCVE Program / NVD first with legacy fallback
Published2026-08-15 13:18:02 UTC
Updated2026-08-19 17:21:11 UTC
DescriptionIn 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) ...

Risk And Classification

Primary CVSS: v3.1 9.8 CRITICAL from 416baaa9-dc9f-4396-8d5f-8c081fb06d67

CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H

EPSS: 0.003490000 probability, percentile 0.280720000 (date 2026-08-19)

VersionSourceTypeScoreSeverityVector
3.1416baaa9-dc9f-4396-8d5f-8c081fb06d67Secondary9.8CRITICALCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
3.1CNADECLARED9.8CRITICALCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H

CVSS v3.1 Breakdown

Attack Vector
Network
Attack Complexity
Low
Privileges Required
None
User Interaction
None
Scope
Unchanged
Confidentiality
High
Integrity
High
Availability
High

CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H

Vendor Declared Affected Products

SourceVendorProductVersionPlatforms
CNA Linux Linux affected f5b321bd37fbec9188feb1f721ab46a5ac0b35da ed1f9be6dc8e2e280b8725e44ccdc6e0cd38640d git Not specified
CNA Linux Linux affected f5b321bd37fbec9188feb1f721ab46a5ac0b35da 1b0843f9e9b9b0b9b4b70d143b67e58163c85b2c git Not specified
CNA Linux Linux affected f5b321bd37fbec9188feb1f721ab46a5ac0b35da 32d4abc8923b0d4046fd63ad6e4917872e44eb6d git Not specified
CNA Linux Linux affected f5b321bd37fbec9188feb1f721ab46a5ac0b35da 63eea41759fd682229c14e0a2205802b46d106f3 git Not specified
CNA Linux Linux affected f5b321bd37fbec9188feb1f721ab46a5ac0b35da c97621a110e386b2dd69e276eb699e1d3cec581d git Not specified
CNA Linux Linux affected f5b321bd37fbec9188feb1f721ab46a5ac0b35da f74554e67ccf04d1fa71069e8c9afa2717e40716 git Not specified
CNA Linux Linux affected f5b321bd37fbec9188feb1f721ab46a5ac0b35da ef5e2c6555d2bb52dfe0e4053a8c6193f9d83b64 git Not specified
CNA Linux Linux affected f5b321bd37fbec9188feb1f721ab46a5ac0b35da db3d0e0e5d4bc5ab4fe445b9f413d1b486508ca5 git Not specified
CNA Linux Linux affected 2.6.34 Not specified
CNA Linux Linux unaffected 2.6.34 semver Not specified
CNA Linux Linux unaffected 5.10.265 5.10.* semver Not specified
CNA Linux Linux unaffected 5.15.216 5.15.* semver Not specified
CNA Linux Linux unaffected 6.1.183 6.1.* semver Not specified
CNA Linux Linux unaffected 6.6.151 6.6.* semver Not specified
CNA Linux Linux unaffected 6.12.103 6.12.* semver Not specified
CNA Linux Linux unaffected 6.18.44 6.18.* semver Not specified
CNA Linux Linux unaffected 7.1.8 7.1.* semver Not specified
CNA Linux Linux unaffected 7.2 * original_commit_for_fix Not specified

References

ReferenceSourceLinkTags
git.kernel.org/stable/c/1b0843f9e9b9b0b9b4b70d143b67e58163c85b2c 416baaa9-dc9f-4396-8d5f-8c081fb06d67 git.kernel.org
git.kernel.org/stable/c/db3d0e0e5d4bc5ab4fe445b9f413d1b486508ca5 416baaa9-dc9f-4396-8d5f-8c081fb06d67 git.kernel.org
git.kernel.org/stable/c/ed1f9be6dc8e2e280b8725e44ccdc6e0cd38640d 416baaa9-dc9f-4396-8d5f-8c081fb06d67 git.kernel.org
git.kernel.org/stable/c/c97621a110e386b2dd69e276eb699e1d3cec581d 416baaa9-dc9f-4396-8d5f-8c081fb06d67 git.kernel.org
git.kernel.org/stable/c/ef5e2c6555d2bb52dfe0e4053a8c6193f9d83b64 416baaa9-dc9f-4396-8d5f-8c081fb06d67 git.kernel.org
git.kernel.org/stable/c/f74554e67ccf04d1fa71069e8c9afa2717e40716 416baaa9-dc9f-4396-8d5f-8c081fb06d67 git.kernel.org
git.kernel.org/stable/c/63eea41759fd682229c14e0a2205802b46d106f3 416baaa9-dc9f-4396-8d5f-8c081fb06d67 git.kernel.org
git.kernel.org/stable/c/32d4abc8923b0d4046fd63ad6e4917872e44eb6d 416baaa9-dc9f-4396-8d5f-8c081fb06d67 git.kernel.org
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