Is CVE-2026-112399 exploited in the wild?

No. Junglewise Threat Intelligence has no report of CVE-2026-112399 being exploited in the wild.

How severe is CVE-2026-112399?

High severity, with a CVSS score of 4, published 19 October 2026.

Which products and versions are affected?

pillow (PyPI) >= 8.1.0, < 13.0.0, ECOSYSTEM:introduced=8.1.0,fixed=13.0.0; Python Pillow Pillow 8.1.0 to 12.x.x (before 13.0.0).

Is there a fix for CVE-2026-112399?

Yes. pillow (PyPI): upgrade to 13.0.0 or later. Junglewise finds every place you run it, drafts the upgrade and applies it once you approve.

How is CVE-2026-112399 attacked?

It is attacked over the network, in a software library.

Am I affected by CVE-2026-112399?

Check whether you run pillow (PyPI) or Python Pillow Pillow at an affected version. Junglewise does that check for you around the clock: connect your code, cloud and domains, and it matches new vulnerabilities like this one against what you actually run and tells you when one reaches you.

CVE-2026-112399: Pillow APNG decompression bomb denial of service

Q: Is there a fix for CVE-2026-112399?

Yes. pillow (PyPI): upgrade to 13.0.0 or later. Junglewise finds every place you run it, drafts the upgrade and applies it once you approve.

Q: How is CVE-2026-112399 attacked?

It is attacked over the network, in a software library.

Q: Am I affected by CVE-2026-112399?

Check whether you run pillow (PyPI) or Python Pillow Pillow at an affected version. Junglewise does that check for you around the clock: connect your code, cloud and domains, and it matches new vulnerabilities like this one against what you actually run and tells you when one reaches you.

CVE-2026-112399 · Severity: high · CVSS 4 · Published 2026-10-19

Pillow is a Python library for image processing. A crafted APNG (animated PNG) image file can trigger excessive memory allocation during image opening, bypassing safety checks meant to prevent such attacks. An attacker can create a malicious image that causes memory exhaustion and denial of service on systems processing untrusted image files.

Technologies: pillow (PyPI), Python Pillow Pillow. Vendors: PyPI, Python Pillow.

Quick answers

Is CVE-2026-112399 exploited in the wild?: No. Junglewise Threat Intelligence has no report of CVE-2026-112399 being exploited in the wild.
How severe is CVE-2026-112399?: High severity, with a CVSS score of 4, published 19 October 2026.
Which products and versions are affected?: pillow (PyPI) >= 8.1.0, < 13.0.0, ECOSYSTEM:introduced=8.1.0,fixed=13.0.0; Python Pillow Pillow 8.1.0 to 12.x.x (before 13.0.0).
Is there a fix for CVE-2026-112399?: Yes. pillow (PyPI): upgrade to 13.0.0 or later. Junglewise finds every place you run it, drafts the upgrade and applies it once you approve.
How is CVE-2026-112399 attacked?: It is attacked over the network, in a software library.
Am I affected by CVE-2026-112399?: Check whether you run pillow (PyPI) or Python Pillow Pillow at an affected version. Junglewise does that check for you around the clock: connect your code, cloud and domains, and it matches new vulnerabilities like this one against what you actually run and tells you when one reaches you.

How to fix

pillow (PyPI): upgrade to 13.0.0 or later
```
pip install "pillow>=13.0.0"
```

Technical details

The vulnerability exists in the PNG image handling code where full-canvas memory allocation for APNG disposal backgrounds occurs before the decompression-bomb check is applied. A crafted APNG with a small first frame, a very large declared canvas size, and background disposal or OP_PREVIOUS operation triggers the over-allocation when Image.open() positions frame zero, without requiring pixel loading or frame iteration. This allows memory exhaustion and denial of service.

Affected products

Python Pillow Pillow 8.1.0 to 12.x.x (before 13.0.0)

Identifiers

CVE-2026-112399
GHSA-5xm2-6676-qcp9

Timeline

2026-10-19: disclosed
2026-10-16: patched: Fixed in version 13.0.0

References

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