CVE-2026-59204: pillow DoS — Exploit & Fix

Description

Pillow is a Python imaging library. From 8.2.0 through 12.2.0, src/libImaging/Jpeg2KDecode.c accumulates total_component_width across every tile in a JPEG2000 image instead of recomputing it per tile, allowing a crafted tiled JPEG2000 file to force substantially higher transient memory usage and trigger out-of-memory failures during decoding. 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-789 CWE-789

CWE-770 CWE-770

Affected Products

Vendor	Product	Versions
python	pillow	8.2.0 — 12.3.0

References

Advisories & Patches

https://github.com/python-pillow/Pillow/commit/13ada41172142f2fd9f0906f615a00ea623a11ca https://github.com/python-pillow/Pillow/pull/9704 https://github.com/python-pillow/Pillow/security/advisories/GHSA-vjc4-5qp5-m44j

Exploits

https://github.com/python-pillow/Pillow/pull/9704 https://github.com/python-pillow/Pillow/security/advisories/GHSA-vjc4-5qp5-m44j

Other References

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

Frequently Asked Questions

What is CVE-2026-59204? +

Pillow is a Python imaging library. From 8.2.0 through 12.2.0, src/libImaging/Jpeg2KDecode.c accumulates total_component_width across every tile in a JPEG2000 image instead of recomputing it per tile, allowing a crafted tiled JPEG2000 file to force substantially higher transient memory usage and trigger out-of-memory failures during decoding. 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-2026-59204? +

CVE-2026-59204 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-2026-59204? +

CVE-2026-59204 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-2026-59204? +

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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