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Not in CISA KEV
HIGH severity

CVE-2021-25290 — pillow

HIGHFix: python-pillow/Pillow@86f02f7

CVE-2021-25290 is a high-severity (CVSS 7.5) Out-of-bounds Write vulnerability in pillow. A fix is available for pillow — see the affected versions and patch details below.

Out-of-bounds Write in Pillow

Also known asBIT-pillow-2021-25290GHSA-8xjq-8fcg-g5hwPYSEC-2021-36
Published
Updated
Affected
1 pkg
Patched
1 / 1
Exploits
None indexed
Exploitation data as of Oct 11, 2026 · OSV.dev, NVD, FIRST.org (EPSS)

EPSS Exploitation Probability

via FIRST.org ↗
2.4%probability of exploitation in next 30 days
Lower Risk0.00%
Lower risk than most CVEs83th percentile — riskier than 83% of all scored CVEsHighest risk
0.00%1.01%2.03%3.04%0.1%2.4%Apr 26Aug 26Oct 26

Probability of exploitation in the next 30 days, from FIRST.org EPSS.

How urgent is this, really

CVE-2021-25290 by exploitation likelihood (EPSS) against impact (CVSS). Outside the shaded patch-first corner.

Where this sits among everything scored

Of 385,987 CVEs with a current EPSS score, this one falls in the < 10% band (highlighted). Counts from FIRST.org, log-scaled.

Real-World Exposure

1 pkg affected
🐍pillow

Real-time download stats are indexed for npm and PyPI packages. This vulnerability affects PyPI packages — download data is not available via public APIs for these ecosystems.

Description

An issue was discovered in Pillow before 8.1.1. In TiffDecode.c, there is a negative-offset memcpy with an invalid size.

Affected Packages

1 total 1 fixed
EcosystemPackageVulnerable rangeFix
🐍PyPIpillowall versions8.1.1pip install --upgrade 'pillow==8.1.1'

Affected Products

2 products · 2 configurations
OS
debian linuxdebian
1 version
9.0
Application
pillowpython
< 8.1.1
range

Detection & mitigation playbook

Open-source dependency

  1. Detect

    Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for pillow, including transitive dependencies — a direct dependency you never call can still pull in a vulnerable version.

  2. Fix

    Update pillow to 8.1.1 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms CVE-2021-25290 is resolved across your whole dependency graph.

  3. Workarounds

    Stop feeding it untrusted input: reject or quarantine files and payloads from unverified sources until you can upgrade, restrict accepted formats to the ones you actually need, and run the parsing or decoding step in a least-privileged sandbox or short-lived worker so a crash or corrupted read cannot reach the rest of the process.

Fixing This On Your OS

If you run this on a Linux distribution, patch through your package manager against the distro's own security advisory below — it tracks the exact backported fix for your release, which can ship on a different timeline (and sometimes a different severity) than the upstream project.

Red HatModerate
Workaround published by Red Hat
Disable the invoice generation feature to mitigate this vulnerability in Red Hat Quay.
Source: Red Hat security advisory for CVE-2021-25290 (CC BY 4.0)
ProductFixed inAdvisory
Red Hat Enterprise Linux 8python-pillow-0:5.1.1-16.el8RHSA-2021:4149
Red Hat Quay 3quay/quay-rhel8:v3.6.0-62RHSA-2021:3917

Frequently Asked Questions

An issue was discovered in Pillow before 8.1.1. In TiffDecode.c, there is a negative-offset memcpy with an invalid size.
O3 Security · Impact-Aware SCA

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CVE-2021-25290: pillow — Fixed in 8.1.1