CVE-2026-111139

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().

References

• https://download.netsurf-browser.org/libs/releases/libnsbmp-0.1.7-src.tar.gz
• https://github.com/netsurf-browser/libnsbmp
• https://github.com/netsurf-browser/libnsbmp/blob/ea063c9f46acb43e90208da14073332b505ef7e7/src/libnsbmp.c#L835-L873
• https://hackmd.io/@haind-pwn/libnsbmp-rle-absolute-pad-and-ico-mask-oob-read
• https://www.vulncheck.com/advisories/netsurf-libnsbmp-through-0.1.7-out-of-bounds-read-via-bmp-decode-mask