CVE-2026-98077: netfilter: nf_conntrack_sip: fix OOB read in sip_skip_whitespace()
In the Linux kernel, the following vulnerability has been resolved:
netfilter: nfconntracksip: fix OOB read in sipskipwhitespace()
sipskipwhitespace() returns dptr unchanged when its own loop exhausts the buffer (dptr == limit), instead of NULL like its sibling sipfollowcontinuation() returns on its own "no more data" path.
ctsipgetheader() only checks for NULL after calling it:
dptr = sipskipwhitespace(dptr, limit); if (dptr == NULL) break; if (dptr != ':' || ++dptr >= limit) break;
so a recognized header name followed only by spaces/tabs running to the exact end of the SIP payload, with no colon, makes the very next statement read one byte past the buffer.
Make both "no more data" outcomes return NULL, matching the convention sipfollowcontinuation() already uses and that both existing callers already check for.
Affected Software
Event History
Frequently Asked Questions
What traffic is needed to trigger this issue?
The affected connection-tracking SIP parser must process a SIP payload containing a recognized header name followed only by spaces or tabs through the exact end of the payload, with no colon present.
How can I determine whether a system is affected?
Check whether the running Linux kernel includes the fix that makes sip_skip_whitespace() return NULL when it reaches the buffer limit. The listed stable kernel references identify commits containing the correction.
What is the immediate mitigation if an updated kernel cannot be deployed?
The provided information does not specify a mitigation. Exposure depends on processing SIP traffic through the affected netfilter connection-tracking SIP parser.