CVE-2026-23457
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,…
Does this matter?
High impact if exploited, but EPSS currently rates exploitation as unlikely (0.43%). Schedule it in the normal patch cycle and watch for a rise in EPSS or a public exploit.
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.
- CVSS 3.1
- 8.6 HIGHCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:L/A:H
- EPSS
- 0.43% probability · 37th percentile
- CISA KEV
- Not listed
- Affected
- linux/linux kernel
- Source
- 416baaa9-dc9f-4396-8d5f-8c081fb06d67
References
- https://git.kernel.org/stable/c/528b4509c9dfc272e2e92d811915e5211650d383Patch
- https://git.kernel.org/stable/c/75fcaee5170e7dbbee778927134ef2e9568b4659Patch
- https://git.kernel.org/stable/c/865dba58958c3a86786f89a501971ab0e3ec6ba9Patch
- https://git.kernel.org/stable/c/b75209debb9adab287b3caa982f77788c1e15027Patch
- https://git.kernel.org/stable/c/cd1b7403ec835f8a0b3f1f7e68ac26af2cb1e42fPatch
- https://git.kernel.org/stable/c/d4f17256544cc37f6534a14a27a9dec3540c2015Patch
- https://git.kernel.org/stable/c/ed81b6a7012485acdb9c6c80735a0b7d8e5e1873Patch
- https://git.kernel.org/stable/c/fbce58e719a17aa215c724473fd5baaa4a8dc57cPatch
- https://cert-portal.siemens.com/productcert/html/ssa-019113.html
- https://cert-portal.siemens.com/productcert/html/ssa-082556.html
Source: NVD record, EPSS from FIRST.org, KEV from CISA. Refreshed daily.