CVE-2026-52986

Technical Description

In the Linux kernel, the following vulnerability has been resolved:

netfilter: nf_conntrack_sip: don't use simple_strtoul

Replace unsafe port parsing in epaddr_len(), ct_sip_parse_header_uri(),

and ct_sip_parse_request() with a new sip_parse_port() helper that

validates each digit against the buffer limit, eliminating the use of

simple_strtoul() which assumes NUL-terminated strings.

The previous code dereferenced pointers without bounds checks after

sip_parse_addr() and relied on simple_strtoul() on non-NUL-terminated

skb data. A port that reaches the buffer limit without a trailing

character is also rejected as malformed.

Also get rid of all simple_strtoul() usage in conntrack, prefer a

stricter version instead. There are intentional changes:

- Bail out if number is > UINT_MAX and indicate a failure, same for

too long sequences.

While we do accept 05535 as port 5535, we will not accept e.g.

'sip:10.0.0.1:005060'. While its syntactically valid under RFC 3261,

we should r

Remediation

Check the references section for vendor advisories and patches from linux. Update linux_kernel to the latest patched version. 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.

Affected Products

References