GNU Emacs < 31.0.91 Heap Over-Read via PBM/PPM/PGM Image Loader (CVE-2026-77219) | HOL Guard CVE

Unknown severity · Source severity not reportedCVE-2026-77219

GNU Emacs < 31.0.91 Heap Over-Read via PBM/PPM/PGM Image Loader

Answer in brief

CVE-2026-77219 records a Unknown severity vulnerability in GNU Emacs < 31.0.91 Heap Over-Read via PBM/PPM/PGM Image Loader. The current sources do not mark it as known exploited. The current feed maps GNU/Emacs (generic). Check affected ranges and fixed versions before updating.

Analysis pending evidence review

HOL Guard separates source facts from reviewed analysis. See the methodology.

Published Aug 21, 2026Updated Aug 21, 2026Source checked Aug 21, 2026First seen by HOL Aug 21, 2026Material review Aug 21, 2026

Upstream Advisory

Key facts

Risk: Unknown severitySource severity not reported
Exploitation: Not marked as known exploited
Affected software: 1 mapped package or product
Fix availability: Available

Why this deserves its current priority

A CVSS score is not reported in the current record. The current sources do not mark it as known exploited. Treat this as a source-backed prioritization signal, not a statement about your environment.

Analysis status

Analysis pending evidence review

Factual feed record only; HOL analysis is not approved for indexing. Read the methodology.

Affected scope and exposure questions

The current feed maps GNU/Emacs (generic). Check affected ranges and fixed versions before updating.

Mapped affected packages and fixed versions
Package	Affected range	Fixed version
GNU/Emacsgeneric	>=0 <31.0.91	31.0.91

Recommended response

Check inventory. Check lockfiles and deployed manifests for GNU/Emacs.
Review the reported fix. Update GNU/Emacs to 31.0.91 if you use the affected versions. Test the change in a non-production environment first.

Evidence timeline and material changes

Published upstream
Aug 21, 2026
Evidence: source:cvelist:source_dates:source-dates:record
Source modified
Aug 21, 2026
Evidence: source:cvelist:source_dates:source-dates:record
First seen by HOL
Aug 21, 2026

Sources and claim methodology

Upstream source description

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.

Quoted source text, attributed separately from HOL analysis.