CVE-2026-112393: Heap-Based Buffer Overflow Flaw in python-pillow Pillow Scores 9.2 on CVSS

A critical heap-based buffer overflow tracked as CVE-2026-112393 has been published in the National Vulnerability Database for python-pillow Pillow, with a CVSS base score of 9.2.

At a glance

CVE

CVE-2026-112393

Product

python-pillow Pillow

CVSS

9.2 Critical

Weakness

heap-based buffer overflow

Exploited

No known exploitation

What is the vulnerability?

The NVD entry states: Pillow is a Python imaging library. From 2.0.0 until 13.0.0, Pillow has a heap buffer overflow and stale-heap disclosure in _tiffWriteProc when saving compressed TIFF data through libtiff to a target without a usable fileno(), such as BytesIO. The callback sizes its allocation from the prior buffer size instead of the current write position, allowing an attacker-controlled out-of-line TIFF tag or retained ICC profile to be copied beyond the allocation after libtiff seeks forward. This overflow can crash the process and may allow code execution. Independently, unwritten alignment gaps in compressed TIFF output larger than 64 KiB can disclose stale heap bytes without a crafted tag. File paths and targets with real file descriptors are unaffected. This issue is fixed in version 13.0.0.

Affected versions

Is it being exploited?

There is no public confirmation of exploitation at the time of publication. It does not appear in CISA's Known Exploited Vulnerabilities catalog. We will update this report if that changes.

What should you do?

• Identify whether the affected product and versions run in your environment.
• Apply the vendor update listed in the advisory as soon as it is available.
• Limit network exposure of the affected service until it is patched.
• Monitor the vendor advisory for updated guidance or exploitation reports.

What to do and how to stay safe: CVE-2026-112393

• Vulnerability severity scores ignore your specific architecture and context.
• Exploitability depends on network exposure and user behavior, not just code flaws.
• Prioritization requires continuous asset inventory and threat intelligence alignment.

Risk-based vulnerability management focuses your limited resources on the flaws that actually threaten your business. Start by mapping your critical assets and checking for active exploits to prioritize your backlog.

Step-by-step guide: Risk-Based Vulnerability Management: Prioritize Fixes by Actual Danger

General security guidance from the Threat Times newsroom. It is not confirmed advice from the organisations named in this story.

Frequently asked questions

What is CVE-2026-112393?

CVE-2026-112393 is a heap-based buffer overflow vulnerability in python-pillow Pillow.

How severe is CVE-2026-112393?

It has a CVSS score of 9.2 Critical.

Is CVE-2026-112393 being exploited?

There is no public confirmation of exploitation at the time of publication.