CVE-2026-112406: Pillow is a Python imaging library

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HIGH 7.5REMOTEUPGRADE

CVE-2026-112406 is a high-severity flaw (CVSS 7.5) affecting pillow. Below: why it ranks where it does, which versions are affected, what to do, and the exact commands.

Pillow is a Python imaging library. From 5.1.0 until 13.0.0, Pillow can enter an infinite loop while rewriting PDF pages. PdfParser.rewrite_pages() follows Parent relationships without detecting a cycle in the page tree. An attacker can supply a cyclic PDF to an application that appends an image to that PDF. This can hold the worker at full CPU and deny service. This issue is fixed in version 13.0.0.

Why this priority

High severity
Public exploit reference
Remotely exploitable, no login, no user action

A fixed release or distro patch exists.

Risk facts

CVSS score	7.5 (High)
Attack vector	Network (remote)
Attack complexity	Low
Privileges needed	None
User interaction	None
EPSS exploit chance	0.4% (top 64%)
CISA exploited list	No
Weakness	CWE-835
Published	2026-10-19
Last modified	2026-10-27

Publisher (CNA): GitHub, Inc. · Vendor: python

Last updated 2026-10-27 · Sources: CVE Program, NVD, CISA KEV, EPSS and vendor advisories · How we score

Am I affected?

Timeline

2026-10-19 22:17 UTCPublished CVE record published
2026-10-27 14:59 UTCUpdated Record last modified

python pillow UPGRADE

Affected: >= 5.1.0 and < 13.0.0

Fixed in: 13.0.0

Safe to downgrade to: a release before 5.1.0

1. Check installed version

apt-cache policy pillow || rpm -q pillow || pillow --version

2. UPGRADE to 13.0.0 (Debian / Ubuntu)

sudo apt update && sudo apt install --only-upgrade pillow

2. UPGRADE (RHEL / Amazon Linux / Fedora)

sudo dnf upgrade pillow

Note

Distros often backport fixes without changing the version number. Confirm with the distro advisory or changelog.

3. If no update is available yet, DOWNGRADE to a release before 5.1.0 (Debian / Ubuntu)

apt-cache madison pillow sudo apt install pillow=<VERSION_BEFORE_5.1.0> sudo apt-mark hold pillow

3. If no update is available yet, DOWNGRADE (RHEL / Amazon Linux / Fedora)

dnf --showduplicates list pillow sudo dnf downgrade pillow-<VERSION_BEFORE_5.1.0> sudo dnf versionlock add pillow

Downgrade risk

Downgrading can break dependent software and may reopen older bugs. Read the distro advisory first and test on a non-production host.

After downgrade

Restart the service, and keep the package held until a fixed release ships.

Verify at the official source NVD · CVE Program · Report a problem with this page
Scores and fixes here are computed automatically from those and other public sources. Confirm with the vendor advisory before changing production systems.

Quick answers

How do I fix CVE-2026-112406?

pillow: upgrade to 13.0.0. Exact commands for each OS are on this page.

Is CVE-2026-112406 being exploited?

CVE-2026-112406 is not on the CISA Known Exploited Vulnerabilities list at the time of the last update. Check again, as this can change.

What does CVE-2026-112406 affect?

CVE-2026-112406 affects pillow. Severity is high (CVSS 7.5). Pillow is a Python imaging library. From 5.1.0 until 13.0.0, Pillow can enter an infinite loop while rewriting PDF pages. PdfParser.rewrite_pages() follows Parent relationships without detecting a cycle in the page tree. An attacker can sup

How urgent is CVE-2026-112406?

Priority 45/100. High severity; Public exploit reference; Remotely exploitable, no login, no user action

Software pages

Python vulnerabilities

Related CVEs

CVE-2026-96778 HIGH 8.8 UPGRADE Pillow is a Python imaging library
CVE-2026-96641 MEDIUM 6.5 UPGRADE Pillow is a Python imaging library
CVE-2026-96640 HIGH 7.5 UPGRADE Pillow is a Python imaging library
CVE-2026-112402 HIGH 7.5 UPGRADE Pillow is a Python imaging library
CVE-2026-112401 HIGH 7.5 UPGRADE Pillow is a Python imaging library

References

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