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.
Exploitability
AV:NAC:LPR:NUI:NScope
S:UImpact
C:LI:LA:H8.6/CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:L/A:H