CVE-2026-40192

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.

What this means for your business

It affects Python Pillow. It matters if your company, or a supplier that handles your data, runs it.
An attacker can use it remotely, over a network, without a login, and without anyone at your company clicking anything.
FIRST's prediction model gives it a 0.7% chance of attack attempts being seen in the next 30 days, ranking above 50% of all known flaws.

What to do

1Check whether your company or your suppliers run Python Pillow, and which version. The affected versions are listed further down this page.
2If you do, apply the vendor's fix. A patch or vendor advisory has been published.

Not sure if your company is exposed?

Fastnexa’s certified penetration testers can check whether attackers could use this flaw, or others like it, against your websites, apps and network. The full test is free for our first 10 founding clients until 31 December 2026.

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Scoring

CVSS: 7.5 (v3.1)
Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
CVSS v4: 8.7
Weakness: CWE-400
Assigned by: security-advisories@github.com

Dates

Published: 2026-04-15
Last modified: 2026-09-10
Sources: NVD

Affected products

Python Pillow10.3.0 - 12.2.0

As listed in the NVD configuration data. Not a statement about your estate.