Linux Kernel up to 7.2-rc5 nf_conntrack_sip nf_conntrack_sip.c ct_sip_get_header use after free

CVSS Meta Temp Score
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Current Exploit Price (≈)
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CTI Interest Score
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9.5$5k-$25k0.00+

Summaryinfo

A vulnerability was found in Linux Kernel up to 6.6.150/6.12.102/6.18.43/7.1.7/7.2-rc5. It has been declared as very critical. Affected by this issue is the function ct_sip_get_header of the file net/netfilter/nf_conntrack_sip.c of the component nf_conntrack_sip. Executing a manipulation can lead to use after free. This vulnerability is handled as CVE-2026-74569. The attack can be executed remotely. There is not any exploit available.

Detailsinfo

A vulnerability was found in Linux Kernel up to 6.6.150/6.12.102/6.18.43/7.1.7/7.2-rc5. It has been declared as very critical. This vulnerability affects the function ct_sip_get_header of the file net/netfilter/nf_conntrack_sip.c of the component nf_conntrack_sip. The manipulation with an unknown input leads to a use after free vulnerability. The CWE definition for the vulnerability is CWE-416. Referencing memory after it has been freed can cause a program to crash, use unexpected values, or execute code. As an impact it is known to affect confidentiality, integrity, and availability. CVE summarizes:

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) ...

The advisory is available at git.kernel.org. This vulnerability was named CVE-2026-74569 since 08/15/2026. The exploitation appears to be easy. The attack can be initiated remotely. No form of authentication is required for a successful exploitation. Technical details are known, but there is no available exploit. The structure of the vulnerability defines a possible price range of USD $5k-$25k at the moment (estimation calculated on 08/15/2026).

Upgrading to version 6.6.151, 6.12.103, 6.18.44, 7.1.8 or 7.2-rc6 eliminates this vulnerability. Applying the patch 63eea41759fd682229c14e0a2205802b46d106f3/c97621a110e386b2dd69e276eb699e1d3cec581d/f74554e67ccf04d1fa71069e8c9afa2717e40716/ef5e2c6555d2bb52dfe0e4053a8c6193f9d83b64/db3d0e0e5d4bc5ab4fe445b9f413d1b486508ca5 is able to eliminate this problem.

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Productinfo

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Name

Version

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Website

CPE 2.3info

CPE 2.2info

CVSSv4info

VulDB Vector: 🔒
VulDB Reliability: 🔍

CVSSv3info

VulDB Meta Base Score: 10.0
VulDB Meta Temp Score: 9.5

VulDB Base Score: 10.0
VulDB Temp Score: 9.5
VulDB Vector: 🔒
VulDB Reliability: 🔍

CVSSv2info

AVACAuCIA
💳💳💳💳💳💳
💳💳💳💳💳💳
💳💳💳💳💳💳
VectorComplexityAuthenticationConfidentialityIntegrityAvailability
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VulDB Base Score: 🔒
VulDB Temp Score: 🔒
VulDB Reliability: 🔍

Exploitinginfo

Class: Use after free
CWE: CWE-416 / CWE-119
CAPEC: 🔒
ATT&CK: 🔒

Physical: No
Local: No
Remote: Yes

Availability: 🔒
Status: Not defined
Price Prediction: 🔍
Current Price Estimation: 🔒

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Threat Intelligenceinfo

Interest: 🔍
Active Actors: 🔍
Active APT Groups: 🔍

Countermeasuresinfo

Recommended: Upgrade
Status: 🔍

0-Day Time: 🔒

Upgrade: Kernel 6.6.151/6.12.103/6.18.44/7.1.8/7.2-rc6
Patch: 63eea41759fd682229c14e0a2205802b46d106f3/c97621a110e386b2dd69e276eb699e1d3cec581d/f74554e67ccf04d1fa71069e8c9afa2717e40716/ef5e2c6555d2bb52dfe0e4053a8c6193f9d83b64/db3d0e0e5d4bc5ab4fe445b9f413d1b486508ca5

Timelineinfo

08/15/2026 Advisory disclosed
08/15/2026 +0 days CVE reserved
08/15/2026 +0 days VulDB entry created
08/15/2026 +0 days VulDB entry last update

Sourcesinfo

Vendor: kernel.org

Advisory: git.kernel.org
Status: Confirmed

CVE: CVE-2026-74569 (🔒)
GCVE (CVE): GCVE-0-2026-74569
GCVE (VulDB): GCVE-100-390886

Entryinfo

Created: 08/15/2026 16:00
Changes: 08/15/2026 16:00 (60)
Complete: 🔍
Cache ID: 216::103

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