OESA-2026-4739: python-pillow security update

Q: Which applications are exposed to the FreeType rendering issue?

Applications using Pillow versions from 10.0.0 until 13.0.0 are exposed when they render attacker-supplied font bytes with a nonzero text stroke width. A malformed font can trigger a glyph-load failure that corrupts memory or crashes the process.

Q: Which applications are exposed to the BMP decoding issue?

Applications using Pillow versions from 9.1.0 until 13.0.0 are exposed if they decode crafted RLE BMP files. A small malicious BMP with a permitted large width can cause memory consumption to grow to hundreds of megabytes or more.

Q: Does exploitation require an authenticated user or interaction from a victim?

The supplied severity vector identifies network access, low attack complexity, no privileges required, and no user interaction. Exploitation still depends on the application processing attacker-controlled font data or RLE BMP content in the affected code paths.

Q: What can be done if updating is not immediately possible?

Avoid processing untrusted font bytes in text rendering with a nonzero stroke width, and avoid decoding untrusted RLE BMP files. Update to Pillow 13.0.0 when possible, as both issues are described as fixed in that version.

Published Nov 11, 2026

Updated

Pillow is the friendly PIL fork by Alex Clark and Contributors. PIL is the Python Imaging \ Library by Fredrik Lundh and Contributors. As of 2019, Pillow development is supported by Tidelift. of CVE-2022-22815,CVE-2022-22816) Security Fix(es):

Pillow is a Python imaging library. From 10.0.0 until 13.0.0, Pillow can free an invalid glyph pointer during FreeType rendering with an active stroker. If FTLoadGlyph fails, cleanup may call FTDoneGlyph on an uninitialized or stale glyph variable. An attacker can supply a malformed font as untrusted bytes to an application that draws text with a nonzero stroke width, forcing the glyph-load failure path. This can corrupt memory or crash the process. This issue is fixed in version 13.0.0.(CVE-2026-112893)

Pillow is a Python imaging library. From 9.1.0 until 13.0.0, BmpRleDecoder.decode() in src/PIL/BmpImagePlugin.py permits crafted RLE BMP delta escapes and absolute-mode runs to append beyond the remaining destlength without a per-branch cap. A delta can add roughly 255 image rows in one iteration, so a kilobyte-sized file with a large but permitted width can expand the data bytearray to hundreds of megabytes or more, causing memory-exhaustion denial of service. This issue is fixed in version 13.0.0.(CVE-2026-96638)

Affected Software

1 affected componentFixes available

openeuler/python-pillow<10.3.0-15.oe2403sp1

10.3.0-15.oe2403sp1

Remediation

Recommended actions to resolve this vulnerability, in priority order.

Upgrade
Upgrade openeuler/python-pillow to a version that resolves this vulnerability.
Fixed in 10.3.0-15.oe2403sp1
Upgrade
Upgrade python-pillow to a version that resolves this vulnerability.
Fixed in 13.0.0

Event History

Nov 11, 2026

Advisory Published

via OSV·12:25 PM

Data Sourced

via OSV·12:25 PM

DescriptionSeverityAffected Software

Child vulnerabilities

Contains the following vulnerabilities.

Frequently Asked Questions

Which applications are exposed to the FreeType rendering issue?

Applications using Pillow versions from 10.0.0 until 13.0.0 are exposed when they render attacker-supplied font bytes with a nonzero text stroke width. A malformed font can trigger a glyph-load failure that corrupts memory or crashes the process.

Which applications are exposed to the BMP decoding issue?

Applications using Pillow versions from 9.1.0 until 13.0.0 are exposed if they decode crafted RLE BMP files. A small malicious BMP with a permitted large width can cause memory consumption to grow to hundreds of megabytes or more.

Does exploitation require an authenticated user or interaction from a victim?

The supplied severity vector identifies network access, low attack complexity, no privileges required, and no user interaction. Exploitation still depends on the application processing attacker-controlled font data or RLE BMP content in the affected code paths.

What can be done if updating is not immediately possible?

Avoid processing untrusted font bytes in text rendering with a nonzero stroke width, and avoid decoding untrusted RLE BMP files. Update to Pillow 13.0.0 when possible, as both issues are described as fixed in that version.

OESA-2026-4739: python-pillow security update

Affected Software

Remediation

Event History

Child vulnerabilities

Frequently Asked Questions

Which applications are exposed to the FreeType rendering issue?

Which applications are exposed to the BMP decoding issue?

Does exploitation require an authenticated user or interaction from a victim?

What can be done if updating is not immediately possible?

Company

Resources

Contact

Frequently Asked Questions

Which applications are exposed to the FreeType rendering issue?

Which applications are exposed to the BMP decoding issue?

Does exploitation require an authenticated user or interaction from a victim?

What can be done if updating is not immediately possible?