What’s Vulnerable › Vulnerabilities

CVE-2026-111139: NetSurf libnsbmp through 0.1.7 Out-of-Bounds Read via bmp_decode_mask

• Severity: medium (CVSS 5.5 v3.1)
• Exploited in the wild: not listed in CISA KEV
• EPSS: 0.1% probability of exploitation in the next 30 days
• Public exploit or detection template: none known
• Published: 2026-10-15 · updated 2026-10-26
• Weakness: CWE-125

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().

Affected products

• NetSurf libnsbmp: through 0.1.7

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

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