python-pillow Pillow up to 12.x APNG Image.open allocation of resources

Summaryinfo

A vulnerability was found in python-pillow Pillow up to 12.x. It has been classified as problematic. This affects the function Image.open of the component APNG Handler. The manipulation leads to allocation of resources. This vulnerability is uniquely identified as CVE-2026-112399. The attack is possible to be carried out remotely. No exploit exists. Upgrading the affected component is recommended.

Detailsinfo

A vulnerability was found in python-pillow Pillow up to 12.x. It has been rated as problematic. This issue affects the function Image.open of the component APNG 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. From 8.1.0 until 13.0.0, Pillow can allocate an APNG disposal background at the full canvas size before applying the decompression-bomb check. A crafted APNG with a small first frame, a very large declared canvas, and background disposal or first-frame OP_PREVIOUS reaches PngImageFile._seek while Image.open() positions frame zero. The full-canvas allocation occurs inside Image.open() without requiring pixel loading or frame iteration. This can exhaust memory and deny service. This issue is fixed in version 13.0.0.

It is possible to read the advisory at github.com. The identification of this vulnerability is CVE-2026-112399 since 10/19/2026. The exploitation is known to be easy. The attack may be initiated remotely. No form of authentication is needed for a successful exploitation. It demands that the victim is doing some kind of user interaction. Technical details of the vulnerability are known, but there is no available exploit. The attack technique deployed by this issue is T1499 according to MITRE ATT&CK.

Upgrading to version 13.0.0 eliminates this vulnerability.

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Productinfo

Type

• Programming Language Software

Vendor

• python-pillow

Name

• Pillow

Version

• 12.x

License

• open-source

Website

• Product: https://github.com/python-pillow/Pillow/

CPE 2.3info

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CPE 2.2info

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