CVE-2026-23457

Name of the Vulnerable Software and Affected Versions The Linux kernel (affected versions not specified)

Description A flaw exists in the sip help tcp() function within the netfilter module. This function parses the SIP Content-Length header using simple strtoul(), which returns an unsigned long, but stores the result in an unsigned int variable clen. On 64-bit systems, values exceeding the maximum value for an unsigned int are truncated before calculating the SIP message boundary. This truncation can lead to miscalculation of the message end, causing trailing data in the TCP segment to be incorrectly processed as a second SIP message through the SDP parser.

Recommendations At the moment, there is no information about a newer version that contains a fix for this vulnerability.