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CVE-2026-23457

Published: April 4, 2026Last modified: April 9, 2026

Description

In the Linux kernel, the following vulnerability has been resolved: netfilter: nf_conntrack_sip: fix Content-Length u32 truncation in sip_help_tcp() sip_help_tcp() parses the SIP Content-Length header with simple_strtoul(), which returns unsigned long, but stores the result in unsigned int clen. On 64-bit systems, values exceeding UINT_MAX are silently truncated before computing the SIP message boundary. For example, Content-Length 4294967328 (2^32 + 32) is truncated to 32, causing the parser to miscalculate where the current message ends. The loop then treats trailing data in the TCP segment as a second SIP message and processes it through the SDP parser. Fix this by changing clen to unsigned long to match the return type of simple_strtoul(), and reject Content-Length values that exceed the remaining TCP payload length.

Severity score breakdown

ParameterValue
Base score8.6
Attack VectorNETWORK
Attack complexityLOW
Privileges requiredNONE
User interactionNONE
ScopeUNCHANGED
ConfidentialityLOW
Integrity impactLOW
Availability impactHIGH
VectorCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:L/A:H

Status

ProductReleasePackageStatus
Alpaquita Linux23 LTSlinux-ltsFixed (6.1.167-r0)
25 LTSlinux-ltsFixed (6.12.80-r0)
Streamlinux-ltsFixed (6.12.80-r0)

References

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