libcss through 0.9.2 contains a NULL pointer dereference vulnerability in mq_parse_media_query() that allows remote
Source GCVE Database
Not known to be exploited · CVSS 7.1 High.
Data as of 27 Oct 2026, 02:27 UTC
CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:P/VC:N/VI:N/VA:H/SC:N/SI:N/SA:NExploitation evidence
Disclosed: evidence found.
CVE published 26 Oct 2026
Detectable: no evidence on record.
No public nuclei template indexed
Weaponised: no evidence on record.
No public exploit code indexed in Metasploit or Exploit-DB
Exploited in the wildExploited: no evidence on record.
Not in CISA KEV and no source reports exploitation
Observed by OffSeq MirageSeen by Mirage: no evidence on record.
No attack traffic recorded by OffSeq Mirage sensors
A missing step is not evidence of safety. Sources: cve.org (opens in a new tab), the Metasploit, Exploit-DB and nuclei-templates index as of 26 Oct 2026.
What to do
Affected software
| Product | Affected | Fixed in |
|---|---|---|
| netsurf-browserlibcss | Affected
| Fixed in– |
GitHublibcsspkg:github/libcssOther threats | Affected
| Fixed in– |
Check your own hosts for these packages with threat-finder (opens in a new tab), our free open-source scanner.
AI-suggested
Users should monitor vendor advisories for updates. Until a fix is released, avoid processing untrusted stylesheets or apply application-level protections to handle malformed media queries safely.
Description
libcss versions through 0.9.2 have a NULL pointer dereference vulnerability in the mq_parse_media_query() function. This flaw allows remote attackers to cause a denial of service by supplying media lists that end with a trailing comma, which can crash parsers like NetSurf when processing @media or @import rules in stylesheets.
References
- nvd.nist.gov/vuln/detail/CVE-2026-116740 (opens in a new tab)
- github.com/netsurf-browser/libcss/commit/006ffc4096040da13690abc380e5f828ec08284d (opens in a new tab)
- github.com/netsurf-browser/libcss (opens in a new tab)
- github.com/netsurf-browser/libcss/blob/release/0.9.2/src/parse/mq.c (opens in a new tab)
- hackmd.io/@haindpwn/libcss-media-list-null-deref (opens in a new tab)
- vulncheck.com/advisories/libcss-through-0.9.2-null-pointer-dereference-via-media-query-parser (opens in a new tab)