CVE-2026-59205: pillow Memory Corruption

Description

Pillow is a Python imaging library. Prior to 12.3.0, Pillow's ImageCms.ImageCmsTransform.apply(im, imOut) API can trigger controlled native heap corruption when the caller supplies an output image whose mode does not match the transform's declared output mode. This issue is fixed in version 12.3.0.

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CVSS v3.1 Score

7.5

HIGH

CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H

EPSS — Exploit Prediction

0.0039

Probability of exploitation

0.32%

Percentile rank

EPSS estimates the probability that this vulnerability will be exploited in the wild within the next 30 days. A higher score means more likely to be exploited.

Weakness Type (CWE)

CWE-787 Out-of-bounds Write

Affected Products

Vendor	Product	Versions
python	pillow	< 12.3.0

References

Advisories & Patches

https://github.com/python-pillow/Pillow/commit/a9ffc42bedf4fc0a7ef8d6486e7f9e81e3397721 https://github.com/python-pillow/Pillow/pull/9715 https://github.com/python-pillow/Pillow/security/advisories/GHSA-9hw9-ch79-4vh6 https://github.com/python-pillow/Pillow/security/advisories/GHSA-9hw9-ch79-4vh6

Exploits

https://github.com/python-pillow/Pillow/security/advisories/GHSA-9hw9-ch79-4vh6 https://github.com/python-pillow/Pillow/security/advisories/GHSA-9hw9-ch79-4vh6

Other References

https://github.com/python-pillow/Pillow/releases/tag/12.3.0

Frequently Asked Questions

What is CVE-2026-59205? +

Pillow is a Python imaging library. Prior to 12.3.0, Pillow's ImageCms.ImageCmsTransform.apply(im, imOut) API can trigger controlled native heap corruption when the caller supplies an output image whose mode does not match the transform's declared output mode. This issue is fixed in version 12.3.0. It has a CVSS v3.1 base score of 7.5 (HIGH).

How severe is CVE-2026-59205? +

CVE-2026-59205 has a CVSS v3.1 score of 7.5 out of 10, rated HIGH. This is a high-severity vulnerability that should be prioritized for patching. The EPSS score is 0.0039, placing it in the 0th percentile for exploitation probability.

What products are affected by CVE-2026-59205? +

CVE-2026-59205 affects products from python, specifically: pillow. Check the affected products table above for specific version ranges.

How do I check if I'm vulnerable to CVE-2026-59205? +

You can use Secably's free Website Scanner to check your website for known vulnerabilities. For infrastructure scanning, use the Port Scanner to identify exposed services that may be affected. Check the vendor advisories linked above for specific patch and version information.

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