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 v3 7.1 HIGH

7.1^/10

CVSS v3 : HIGH

Vector :

Exploitability : 1.8 / Impact : 5.2

Attack Vector LOCAL

Attack Complexity LOW

Privileges Required NONE

User Interaction REQUIRED

Confidentiality Impact HIGH

Integrity Impact NONE

Availability Impact HIGH

Scope UNCHANGED

References

Link	Resource
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

Configurations

No configuration.

History

12 Oct 2026, 16:10

Type	Values Removed	Values Added
Summary		(es) GNU Emacs anterior a la versión 31.0.91 contiene un desbordamiento de entero en el cargador de imágenes PBM/PPM/PGM que permite a un atacante filtrar el contenido de la memoria heap al proporcionar una imagen manipulada con grandes dimensiones y un índice de color máximo elevado. El cargador de imágenes multiplica las dimensiones de la imagen y el número de canales utilizando aritmética de enteros con signo; para valores suficientemente grandes, el resultado se ajusta a un número negativo, eludiendo la comprobación de límites y haciendo que el lector de píxeles acceda a la memoria heap más allá del final del búfer asignado. El contenido sobre-leído se interpreta como valores de color de píxel y se renderiza en pantalla.

Information

Published : 2026-08-21 21:17

Updated : 2026-10-12 16:10

NVD link : CVE-2026-77219

Mitre link : CVE-2026-77219

CVE.ORG link : CVE-2026-77219

JSON object : View

Products Affected

No product.

CWE

CWE-125

Out-of-bounds Read

CWE-190

Integer Overflow or Wraparound

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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."}, {"lang": "es", "value": "GNU Emacs anterior a la versi\u00f3n 31.0.91 contiene un desbordamiento de entero en el cargador de im\u00e1genes PBM/PPM/PGM que permite a un atacante filtrar el contenido de la memoria heap al proporcionar una imagen manipulada con grandes dimensiones y un \u00edndice de color m\u00e1ximo elevado. El cargador de im\u00e1genes multiplica las dimensiones de la imagen y el n\u00famero de canales utilizando aritm\u00e9tica de enteros con signo; para valores suficientemente grandes, el resultado se ajusta a un n\u00famero negativo, eludiendo la comprobaci\u00f3n de l\u00edmites y haciendo que el lector de p\u00edxeles acceda a la memoria heap m\u00e1s all\u00e1 del final del b\u00fafer asignado. El contenido sobre-le\u00eddo se interpreta como valores de color de p\u00edxel y se renderiza en pantalla."}], "lastModified": "2026-10-12T16:10:00.220", "sourceIdentifier": "disclosure@vulncheck.com"}