CVE-2026-66758
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Integer Overflow Leading to Heap Buffer Overflow in GIMP FITS Plugin

Vulnerability report for CVE-2026-66758, including description, CVSS score, EPSS score, affected products, exploitability, helpful resources, and attack-flow context.

Publication date: 2026-07-27

Last updated on: 2026-07-27

Assigner: Red Hat, Inc.

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.

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Meta Information

Published
2026-07-27
Last Modified
2026-07-27
Generated
2026-07-28
AI Q&A
2026-07-27
EPSS Evaluated
N/A
NVD
EUVD

Affected Vendors & Products

Showing 2 associated CPEs
Vendor Product Version / Range
gimp gimp *
gnome gimp *

Helpful Resources

Exploitability

CWE
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KEV
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CWE ID Description
CWE-190 The product performs a calculation that can produce an integer overflow or wraparound when the logic assumes that the resulting value will always be larger than the original value. This occurs when an integer value is incremented to a value that is too large to store in the associated representation. When this occurs, the value may become a very small or negative number.

Attack-Flow Graph

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Executive Summary

This vulnerability is a heap-based buffer overflow in GIMP's file-fits plugin. It occurs when processing a FITS image file with large width and height values. The plugin uses signed 32-bit integers to calculate memory allocation, which can overflow if the product of width and height exceeds 2^31. This leads to an undersized buffer, causing a buffer overflow when writing pixel data. The flaw may allow arbitrary code execution or denial of service.

Detection Guidance

Monitor GIMP processes handling FITS files for crashes or memory corruption errors. Check system logs for segmentation faults or heap overflow warnings during image processing. Use tools like AddressSanitizer (ASan) or Valgrind to detect heap-based buffer overflows when GIMP processes FITS files.

Impact Analysis

If you process a malicious FITS image file with this vulnerability, it could corrupt memory on your system. This may lead to arbitrary code execution, allowing an attacker to take control of your system. Alternatively, it could cause a denial of service, crashing the application or system. The impact depends on the privileges of the user running GIMP.

Compliance Impact

This vulnerability could impact compliance by enabling unauthorized code execution or data corruption. For GDPR, it may risk unauthorized access to personal data. For HIPAA, it could compromise protected health information. Organizations must mitigate this flaw to maintain compliance with data protection and security regulations.

Mitigation Strategies

Update GIMP to the latest version that patches this flaw. Avoid opening untrusted FITS files until patched. Disable the file-fits plugin if not required. Implement file integrity monitoring to detect suspicious image files.

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