CVE-2026-42309: Pillow is a Python imaging library

Routine

MEDIUM 5.5UPGRADE

CVE-2026-42309 is a medium-severity flaw (CVSS 5.5) 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 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 ve

Why this priority

No elevated risk signals yet

A fixed release or distro patch exists.

Risk facts

CVSS score	5.5 (Medium)
Attack vector	Local
Attack complexity	Low
Privileges needed	Low
User interaction	None
EPSS exploit chance	0.1% (top 97%)
CISA exploited list	No
Weakness	CWE-122
Published	2026-05-09
Last modified	2026-07-24

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

Last updated 2026-07-24 · Sources: CVE Program, NVD, CISA KEV, EPSS and vendor advisories · How we score

Am I affected?

Timeline

2026-05-09 06:16 UTCPublished CVE record published
2026-07-24 21:10 UTCUpdated Record last modified

python pillow UPGRADE

Affected: >= 11.2.1 and < 12.2.0

Fixed in: 12.2.0

Safe to downgrade to: a release before 11.2.1

1. Check installed version

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

2. UPGRADE to 12.2.0 (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 11.2.1 (Debian / Ubuntu)

apt-cache madison pillow sudo apt install pillow=<VERSION_BEFORE_11.2.1> 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_11.2.1> 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-2026-42309?

pillow: upgrade to 12.2.0. Exact commands for each OS are on this page.

Is CVE-2026-42309 being exploited?

CVE-2026-42309 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-2026-42309 affect?

CVE-2026-42309 affects pillow. Severity is medium (CVSS 5.5). 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 cau

How urgent is CVE-2026-42309?

Priority 20/100. No elevated risk signals yet.

Software pages

Python vulnerabilities

Related CVEs

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
CVE-2026-112400 HIGH 7.5 UPGRADE Pillow is a Python imaging library
CVE-2026-112399 HIGH 7.5 UPGRADE Pillow is a Python imaging library
CVE-2026-112398 CRITICAL 9.8 UPGRADE Pillow is a Python imaging library

References

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