Security advisory for libcss

Advisory overview

libcss through 0.9.2 contains a NULL pointer dereference vulnerability in mq_parse_media_query() that allows remote attackers to crash consumers by supplying media lists ending in a comma. Attackers can serve a stylesheet whose @media or @import media list has a trailing comma, causing NetSurf or other parsers to crash.

Related references

• https://github.com/netsurf-browser/libcss
• https://github.com/netsurf-browser/libcss/blob/release/0.9.2/src/parse/mq.c#L984
• https://github.com/netsurf-browser/libcss/commit/006ffc4096040da13690abc380e5f828ec08284d
• https://hackmd.io/@haindpwn/libcss-media-list-null-deref
• https://www.vulncheck.com/advisories/libcss-through-0.9.2-null-pointer-dereference-via-media-query-parser