Medium severity · published Oct 26, 2026
CVE-2026-116740
libcss through 0.9.2 NULL Pointer Dereference via Media-Query Parser
New
6.5
CVSS
0.3%
EPSS
No
On KEV
Description
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.
CVSS vector
CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:N/I:N/A:H
Attack vector
Network
Complexity
Low
Privileges
None
User interaction
Required
Confidentiality
None
Integrity
None
Availability
High
Scope
Unchanged
Exploitation
Is it being used?
Exploit prediction (EPSS)0.3% · higher than 26% of CVEs
Exploited in the wildNo evidence yet
CISA KEVNot listed
Ransomware campaign useNot known
Affected products
Which versions
LI
libcss · netsurf-browser
through 0.9.2 · source: vendor
References
NVD
https://nvd.nist.gov/vuln/detail/CVE-2026-116740
CVE.org
https://www.cve.org/CVERecord?id=CVE-2026-116740
github.com
https://github.com/netsurf-browser/libcss
github.com
https://github.com/netsurf-browser/libcss/blob/release/0.9.2/src/parse/mq.c#L984
github.com
https://github.com/netsurf-browser/libcss/commit/006ffc4096040da13690abc380e5f828ec08284d
hackmd.io
https://hackmd.io/@haindpwn/libcss-media-list-null-deref
www.vulncheck.com
https://www.vulncheck.com/advisories/libcss-through-0.9.2-null-pointer-dereference-via-media-query-parser