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CVE-2026-42309

MEDIUMCVSS 5.1/10EPSS 0.13%

Last modified

CVE-2026-42309 is a medium-severity vulnerability rated 5.1/10 on the CVSS scale. Pillow is a Python imaging library. From version 11.2.1 to before version 12.2.0, passing nested lists as coordinates to APIs that accept coordinates such as ImagePath.Path, ImageDraw.ImageDraw.polygon and ImageDraw.ImageDraw.line could cause a heap buffer overflow, as nested lists were recursively unpacked beyond the allocated buffer. EPSS estimates a 0.13% chance of exploitation in the next 30 days.

Description

Pillow is a Python imaging library. From version 11.2.1 to before version 12.2.0, passing nested lists as coordinates to APIs that accept coordinates such as ImagePath.Path, ImageDraw.ImageDraw.polygon and ImageDraw.ImageDraw.line could cause a heap buffer overflow, as nested lists were recursively unpacked beyond the allocated buffer. Coordinate lists are now validated to contain exactly two numeric coordinates. This issue has been patched in version 12.2.0.

Metrics

CVSS 3.1
5.5/10

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

CVSS 4.0
5.1/10

CVSS:4.0/AV:L/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:L/SC:N/SI:N/SA:N/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X

EPSS Probability
0.13%

3.1th percentile

Probability of exploitation in the next 30 days. Learn more

Weakness Enumeration

Affected Software

VendorProductVersions
PythonPillow>= 11.2.1, < 12.2.0

References

Timeline

Published
Last Modified
Status
Analyzed

Frequently Asked Questions

What is CVE-2026-42309?
Pillow is a Python imaging library. From version 11.2.1 to before version 12.2.0, passing nested lists as coordinates to APIs that accept coordinates such as ImagePath.Path, ImageDraw.ImageDraw.polygon and ImageDraw.ImageDraw.line could cause a heap buffer overflow, as nested lists were recursively unpacked beyond the allocated buffer. Coordinate lists are now validated to contain exactly two numeric coordinates. This issue has been patched in version 12.2.0.
How severe is CVE-2026-42309?
CVE-2026-42309 has a CVSS score of 5.1/10 (MEDIUM severity). The EPSS model estimates a 0.13% probability of exploitation in the next 30 days.
How do I fix CVE-2026-42309?
Check the vendor references and advisories linked above for patched versions and mitigation guidance. You can also run a Strix scan to test if your systems are affected.

Are you affected by CVE-2026-42309?

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Source: NVD / NIST