CVE-2026-66758
PoC massHeap buffer overflow in GIMP FITS plugin via integer overflow
An integer overflow (CWE-190) in the file-fits plugin bundled with GIMP causes image width and height values from a FITS file to be multiplied using signed 32-bit arithmetic; when a crafted file sets both dimensions large enough that the product exceeds 2^31, the plugin allocates an undersized heap buffer, and cfitsio's subsequent write of a full pixel row overflows it. The flaw is triggered when a user opens or processes a maliciously crafted FITS image in GIMP, consistent with the CVSS local attack vector requiring user interaction (AV:L/UI:R). Successful exploitation corrupts heap memory and can potentially lead to arbitrary code execution with the victim user's privileges, or crash the application in a denial of service. Anyone running GIMP with the FITS loader enabled is affected, including GIMP packages shipped with Red Hat Enterprise Linux. There are no reports of in-the-wild exploitation (not in CISA KEV; EPSS 0.3%), but a public issue with a proof-of-concept reference exists on the GNOME GitLab tracker.
What to do: Update GIMP via your distribution's package channel once a patched release is available and watch for a Red Hat security advisory covering Enterprise Linux (fixed version numbers are not given in the source data). As an interim mitigation, avoid opening untrusted .fits files in GIMP and check whether the file-fits plugin is enabled in your build. Public PoC details are tracked in GNOME GitLab issue 16528.
| GIMP (file-fits plugin) | — |
| redhat Red Hat Enterprise Linux (ships GIMP) | — |
Order-of-magnitude estimate by the model from install counts, market share and public scan data it knows; verify before quoting.
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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