CVE-2026-111139 NetSurf libnsbmp through 0.1.7 Out-of-Bounds Read via bmp_decode_mask
Attackers can cause a crash or read memory by supplying crafted ICO files to applications using the NetSurf libnsbmp library.
- Exploited in the wild
- Not known
- Login needed
- Not needed
- Attackable
- Local or same network only
- Victim action needed
- A user has to click or open something
- Fix
- None listed
What is CVE-2026-111139?
CVE-2026-111139 is a medium-severity memory corruption vulnerability in NetSurf libnsbmp, published on 15 Oct 2026. It can only be exploited from the same machine or local network, and only if a user opens a file or follows a link.
Official description
NetSurf libnsbmp through 0.1.7 contains an out-of-bounds read vulnerability in bmp_decode_mask() that allows attackers to read one byte past the image buffer by supplying crafted ICO files. Attackers can provide an ICO whose inner bitmap width is not a multiple of 8, causing a heap over-read that can crash applications calling bmp_decode().
Weakness: CWE-125
Which versions are affected by CVE-2026-111139?
How do I fix CVE-2026-111139?
No fix has been published for CVE-2026-111139 yet. Limit exposure of the affected software until one is available.
Upgrade to the fixed version. Memory-safe languages, compiler hardening and fuzzing prevent most new cases. More about Memory corruption.
Is CVE-2026-111139 being exploited?
It is not confirmed as exploited in the wild, but public exploit code for CVE-2026-111139 exists.
Sources
Also known as GHSA-j4g8-9gm4-w4v9, UBUNTU-CVE-2026-111139.