Bug 2521196 (CVE-2026-77219)

Summary: CVE-2026-77219 emacs: GNU Emacs: Heap over-read leading to information disclosure via crafted image
Product: [Other] Security Response Reporter: OSIDB Bzimport <bzimport>
Component: vulnerabilityAssignee: Product Security <prodsec-ir-bot>
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Severity: high Docs Contact:
Priority: high    
Version: unspecifiedCC: rhel-process-autobot, watson-tool-maintainers
Target Milestone: ---Keywords: Security
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Hardware: All   
OS: Linux   
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A flaw was found in GNU Emacs. An integer overflow in the PBM/PPM/PGM image loader allows a remote attacker to leak heap memory contents. 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. This enables the pixel reader to access and render sensitive information from heap memory.
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oVirt Team: --- RHEL 7.3 requirements from Atomic Host:
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Bug Depends On: 2523273    
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Description OSIDB Bzimport 2026-08-21 20:49:03 UTC 
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.