CVE-2026-112898: Pillow is a Python imaging library

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MEDIUM 5.3REMOTEUPGRADE

CVE-2026-112898 is a medium-severity flaw (CVSS 5.3) 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 9.1.0 until 13.0.0, Pillow can disclose uninitialized stack memory when Image.quantize() uses an empty palette. ImagingPaletteCacheUpdate() leaves a local cache array uninitialized when the palette has zero entries, and the conversion path emits those bytes as output pixel indices. An attacker who controls the palette image can obtain stack contents from a returned PNG or GIF. This can disclose addresses a

Why this priority

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

A fixed release or distro patch exists.

Risk facts

CVSS score	5.3 (Medium)
Attack vector	Network (remote)
Attack complexity	Low
Privileges needed	None
User interaction	None
EPSS exploit chance	0.4% (top 68%)
CISA exploited list	No
Weakness	CWE-457
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 14:55 UTCUpdated Record last modified

python pillow UPGRADE

Affected: >= 9.1.0 and < 13.0.0

Fixed in: 13.0.0

Safe to downgrade to: a release before 9.1.0

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 9.1.0 (Debian / Ubuntu)

apt-cache madison pillow sudo apt install pillow=<VERSION_BEFORE_9.1.0> 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_9.1.0> 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-2026-112898?

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

Is CVE-2026-112898 being exploited?

CVE-2026-112898 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-2026-112898 affect?

CVE-2026-112898 affects pillow. Severity is medium (CVSS 5.3). Pillow is a Python imaging library. From 9.1.0 until 13.0.0, Pillow can disclose uninitialized stack memory when Image.quantize() uses an empty palette. ImagingPaletteCacheUpdate() leaves a local cache array uninitialized when the palette h

How urgent is CVE-2026-112898?

Priority 37/100. 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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