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CVE-2026-23457

8.6 · HIGH

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 h…

Published Apr 3, 2026EPSS 0.43%

Overview

CVE-2026-23457 is a high-severity vulnerability. It was published on April 3, 2026 and has a CVSS 3.1 base score of 8.6 (HIGH).

This vulnerability has a CVSS 3.1 base score of 8.6, rated HIGH. It can be exploited remotely over the network. No authentication or special privileges are required for exploitation.

Technical 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.

Remediation

Check the references section for vendor advisories, patches, and mitigation guidance. If immediate patching is not possible, review the CVSS vector to understand the attack surface and apply compensating controls such as network segmentation or access restrictions.

References

Refgit.kernel.org/stable/c/528b4509c9dfc272e2e92d811915e5211650d383Refgit.kernel.org/stable/c/75fcaee5170e7dbbee778927134ef2e9568b4659Refgit.kernel.org/stable/c/865dba58958c3a86786f89a501971ab0e3ec6ba9Refgit.kernel.org/stable/c/b75209debb9adab287b3caa982f77788c1e15027Refgit.kernel.org/stable/c/cd1b7403ec835f8a0b3f1f7e68ac26af2cb1e42fRefgit.kernel.org/stable/c/d4f17256544cc37f6534a14a27a9dec3540c2015Refgit.kernel.org/stable/c/ed81b6a7012485acdb9c6c80735a0b7d8e5e1873Refgit.kernel.org/stable/c/fbce58e719a17aa215c724473fd5baaa4a8dc57cRefcert-portal.siemens.com/productcert/html/ssa-019113.htmlRefcert-portal.siemens.com/productcert/html/ssa-082556.html

How CyberStrike helps

Frequently asked questions

What is CVE-2026-23457?

CVE-2026-23457 is a high-severity vulnerability. It was published on April 3, 2026 and has a CVSS 3.1 base score of 8.6 (HIGH).

How severe is CVE-2026-23457?

This vulnerability has a CVSS 3.1 base score of 8.6, rated HIGH. It can be exploited remotely over the network. No authentication or special privileges are required for exploitation.

How do I fix or remediate CVE-2026-23457?

Check the references section for vendor advisories, patches, and mitigation guidance. If immediate patching is not possible, review the CVSS vector to understand the attack surface and apply compensating controls such as network segmentation or access restrictions.

How can CyberStrike help with CVE-2026-23457?

CyberStrike is an open-source, AI-augmented pentesting engine. Rather than flag a version number, it tests whether an issue like CVE-2026-23457 is actually reachable in your own applications and APIs, then verifies each finding before reporting it. That tells you if the weakness is a real, exploitable risk in your environment or a false positive you can safely deprioritize.

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