Pillow up to 12.1.x FITS Image allocation of resources

Summaryinfo

A vulnerability, which was classified as problematic, has been found in Pillow up to 12.1.x. This affects an unknown function of the component FITS Image Handler. The manipulation leads to allocation of resources. This vulnerability is uniquely identified as CVE-2026-40192. The attack is possible to be carried out remotely. No exploit exists. It is advisable to upgrade the affected component.

Detailsinfo

A vulnerability was found in Pillow up to 12.1.x and classified as problematic. This issue affects an unknown functionality of the component FITS Image Handler. The manipulation with an unknown input leads to a allocation of resources vulnerability. Using CWE to declare the problem leads to CWE-770. The product allocates a reusable resource or group of resources on behalf of an actor without imposing any restrictions on the size or number of resources that can be allocated, in violation of the intended security policy for that actor. Impacted is availability. The summary by CVE is:

Pillow is a Python imaging library. Versions 10.3.0 through 12.1.1 did not limit the amount of GZIP-compressed data read when decoding a FITS image, making them vulnerable to decompression bomb attacks. A specially crafted FITS file could cause unbounded memory consumption, leading to denial of service (OOM crash or severe performance degradation). If users are unable to immediately upgrade, they should only open specific image formats, excluding FITS, as a workaround.

It is possible to read the advisory at github.com. The identification of this vulnerability is CVE-2026-40192 since 04/09/2026. The exploitation is known to be easy. The attack may be initiated remotely. No form of authentication is needed for a successful exploitation. The technical details are unknown and an exploit is not publicly available. The attack technique deployed by this issue is T1499 according to MITRE ATT&CK.

Upgrading to version 12.2.0 eliminates this vulnerability. Applying the patch 3cb854e8b2bab43f40e342e665f9340d861aa628 is able to eliminate this problem. The bugfix is ready for download at github.com. The best possible mitigation is suggested to be upgrading to the latest version.

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Productinfo

Name

• Pillow

Version

• 12.0
• 12.1

License

• open-source

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CPE 2.2info

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