In the Linux kernel, the following vulnerability has been resolved: netfilter: nf_conntrack_sip: fix OOB read in sip_skip_whitespace() sip_skip_whitespace() returns dptr unchanged when its own loop exhausts the buffer (dptr == limit), instead of NULL like its sibling sip_follow_continuation() returns on its own "no more data" path. ct_sip_get_header() only checks for NULL after calling it: dptr = sip_skip_whitespace(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 sip_follow_continuation() already uses and that both existing callers already check for.
https://git.kernel.org/stable/c/e8f8231824b5815f57ce62cba116e511b10196de
https://git.kernel.org/stable/c/60c012b2d05e1558b0f30ea3f15a2c3ca2f24d94
https://git.kernel.org/stable/c/4be8380e3af008f418f97992c06f23be649a430d
https://git.kernel.org/stable/c/4a30aa2ba007db18210dd52219ecbd5528c03523