Heap disclosure via image-size integer overflow
Published Aug 21, 2026 · Updated Aug 21, 2026
Integer overflow in GNU Emacs before 31.0.91 allows context-dependent attackers to disclose heap memory through a crafted PBM, PPM, or PGM image. The pbm_load function in src/image.c multiplies height, width, sample size, and channel count as signed integers, so wraparound defeats its end-of-buffer check. The image must be opened or displayed; the resulting out-of-bounds pixel reads render heap contents and can interrupt the editor.
Summary
What happened
Integer overflow in GNU Emacs before 31.0.91 allows context-dependent attackers to disclose heap memory through a crafted PBM, PPM, or PGM image. The pbm_load function in src/image.c multiplies height, width, sample size, and channel count as signed integers, so wraparound defeats its end-of-buffer check. The image must be opened or displayed; the resulting out-of-bounds pixel reads render heap contents and can interrupt the editor.
The record
- CVE
- CVE-2026-77219
- Published
- Aug 21, 2026
- Updated
- Aug 21, 2026
- Vendor
- The GnuPG Project
- Product
- GNU Emacs
- Classifications
- CWE-190, CWE-125, T1204.002
- Attack vector
- local
- Privileges
- unauthenticated
Timeline
How it unfolded
- Aug 21, 2026CVE publishedPublication date reported by the CVE source.
- Aug 21, 2026Record updatedLatest update available in the CVE record.
Exploitability
Present is not the same as exploitable
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Is a vulnerable build present?
Compare these published version ranges with your installed build and any vendor patches.
- Affected versionversion=0 <31.0.91
What conditions does exploitation require?
What is affected?
Published CVSS scores
CVSS describes severity. EPSS estimates exploitation probability.
Attacks
What attackers are doing with it
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Weakness, pattern, technique
Public exploit references
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Technologies
Your stack
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Your stack
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