CVE-2026-77219

GNU Emacs before 31.0.91 contains an integer overflow in the PBM/PPM/PGM image loader that allows an attacker to leak heap memory contents by supplying a crafted image with large dimensions and an elevated max color index. The image loader multiplies image dimensions and channel count using signed integer arithmetic; for sufficiently large values, the result wraps to a negative number, bypassing the bounds check and causing the pixel reader to access heap memory past the end of the allocated buffer. The over-read contents are interpreted as pixel color values and rendered on screen.

CVSS 4.0

6.9CVSS:4.0/AV:L/AC:L/AT:N/PR:N/UI:P/VC:H/VI:N/VA:H/SC:N/SI:N/SA:N

CVSS 3.1

7.1CVSS:3.1/AV:L/AC:L/PR:N/UI:R/S:U/C:H/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)

CWEs

CWE-125, CWE-190

Published

2026-08-21

Modified

2026-10-12

Record from

the NVD, synced 2026-10-19

References

• https://debbugs.gnu.org/cgi/bugreport.cgi?bug=81344
• https://github.com/emacs-mirror/emacs/commit/b07e634e4cf45162ae0178e32092b040587f2c6c
• https://github.com/emacs-mirror/emacs/releases/tag/emacs-31.0.91
• https://www.vulncheck.com/advisories/gnu-emacs-heap-over-read-via-pbm-ppm-pgm-image-loader

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