CVE-2026-66758 Gimp: integer overflow in file-fits plugin causes a heap-based buffer overflow on crafted fits images

Description

A flaw was found in the file-fits plugin in GIMP. When processing a FITS image file, the plugin calculates memory allocation sizes using signed 32-bit integers for width and height. If a crafted file sets both values to large values, their product exceeds 2^31 and overflows, resulting in an undersized heap-based buffer allocation. This integer overflow issue results in a heap-based buffer overflow when cfitsio subsequently writes a full row of pixels in the buffer, causing memory corruption, potentially leading to arbitrary code execution or a denial of service.

Exploitable with local access to the machine, without an account and if a user takes an action; an attacker can seriously compromise confidentiality, integrity or availability.

Attack vector

Local

Attack complexity

Low

Privileges required

None

Interaction

Required

Scope

Unchanged

Confidentiality

High

Integrity

High

Availability

High

Affected products and versions