CVE-2026-111139

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().

CVSS 4.0

6.8CVSS:4.0/AV:L/AC:L/AT:N/PR:N/UI:P/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N

CVSS 3.1

5.5CVSS:3.1/AV:L/AC:L/PR:N/UI:R/S:U/C:N/I:N/A:H

EPSS

0.1% chance of exploitation in the next 30 days; higher than 2% of CVEs (scores of 2026-10-25)

CWE

CWE-125

Published

2026-10-15

Modified

2026-10-16

Record from

the NVD, synced 2026-10-19

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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