High [CVE-2026-77219] Heap over-read leading to information disclosure via crafted image
This high-severity Red Hat Linux advisory covers CVE-2026-77219 affecting Red Hat Enterprise Linux 10, Red Hat Enterprise Linux 6, Red Hat Enterprise Linux 7.
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Summary
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. By supplying a specially crafted image with large dimensions and an elevated maximum color index, the image loader's internal calculations can wrap to a negative number, bypassing memory bounds checks.
Red Hat severity: Important — CVSS 7.1 (CVSS:3.1/AV:L/AC:L/PR:N/UI:R/S:U/C:H/I:N/A:H). Weakness: CWE-125.
Affected Red Hat products: Red Hat Enterprise Linux 10; Red Hat Enterprise Linux 6; Red Hat Enterprise Linux 7; Red Hat Enterprise Linux 8; Red Hat Enterprise Linux 9. Will not fix / out of support: Red Hat Enterprise Linux 6.
Red Hat does not currently list a fixing RHSA for this CVE.
Affected products named by the advisory: Red Hat package: emacs.
- < 31.0.91
Official advisory · high-confidence parse· fetched 1 hour ago·verify at source
Fixed versions
No fixed release is recorded yet. That does not prove no patch exists — confirm against the vendor advisory.
Official advisory · high-confidence parse· fetched 1 hour ago·verify at source
Mitigation checklist
- To mitigate this issue, users should avoid opening or displaying untrusted PBM, PPM, or PGM image files within GNU Emacs. Exercise caution when handling image files from unknown or unverified sources.
Official advisory · high-confidence parse· fetched 1 hour ago·verify at source
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