CVE-2026-23457
Description
A flaw was found in the Linux kernel's netfilter subsystem, specifically within the nf_conntrack_sip module. This vulnerability arises from an integer truncation error when processing the Content-Length header in Session Initiation Protocol (SIP) messages. On 64-bit systems, large Content-Length values are silently truncated, causing the system to misinterpret the boundary of SIP messages. This can lead to the incorrect parsing of network traffic, potentially allowing an attacker to bypass security policies or trigger unintended processing of data.
Statement
Truncating Content-Length to 32 bits mis-positions SIP message boundaries so trailing bytes may be parsed as a second message through SDP handling. Requires SIP traffic through the conntrack helper; the effect is parser confusion and possible policy bypass, not a classic buffer overflow.
Mitigation
To mitigate this issue, prevent the nf_conntrack_sip module from being loaded. See https://access.redhat.com/solutions/41278 for instructions.
Common Vulnerability Scoring System (CVSS) Score Details
Info alert:Important note
CVSS scores for open source components depend on vendor-specific factors (e.g. version or build chain). Therefore, Red Hat's score and impact rating can be different from NVD and other vendors. Red Hat remains the authoritative CVE Naming Authority (CNA) source for its products and services (see Red Hat classifications).
The following CVSS metrics and score provided are preliminary and subject to review.
CVSS v3 Score Breakdown
| Red Hat | NVD | cve.org | |
|---|---|---|---|
| Base Score | 5.3 | N/A | 8.6 |
| Attack Vector | Local | N/A | Network |
| Attack Complexity | High | N/A | Low |
| Privileges Required | Low | N/A | None |
| User Interaction | None | N/A | None |
| Scope | Unchanged | N/A | Unchanged |
| Confidentiality | None | N/A | Low |
| Integrity Impact | Low | N/A | Low |
| Availability Impact | High | N/A | High |
Vector
Red Hat: CVSS:3.1/AV:L/AC:H/PR:L/UI:N/S:U/C:N/I:L/A:H
cve.org: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:L/A:H
Understanding the Weakness (CWE)
Other,Integrity
Technical Impact: Unexpected State; Quality Degradation
The program could wind up using the wrong number and generate incorrect results. If the number is used to allocate resources or make a security decision, then this could introduce a vulnerability.
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