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MEDIUM severity

GHSA-r73j-pqj5-w3x7 — pillow

MEDIUMFix: python-pillow/Pillow#9519

GHSA-r73j-pqj5-w3x7 is a medium-severity (CVSS 5.5) CWE-835 vulnerability in pillow. A fix is available for pillow — see the affected versions and patch details below.

Pillow has a PDF Parsing Trailer Infinite Loop (DoS)

Also known asBIT-pillow-2026-42310CVE-2026-42310PYSEC-2026-2874
Published
May 4, 2026
Updated
Sep 10, 2026
Affected
1 pkg
Patched
1 / 1
Exploits
None indexed
Exploitation data as of Sep 24, 2026 · OSV.dev, NVD, FIRST.org (EPSS)

Exploitation Status

No confirmed exploitation observed yet

  • CISA’s own triage has not observed active exploitation or public proof-of-concept code for this CVE as of its last assessment.

Exploitation and automatability from CISA’s SSVC triage for GHSA-r73j-pqj5-w3x7.

EPSS Exploitation Probability

via FIRST.org ↗
0.2%probability of exploitation in next 30 days
Lower Risk0.00%
Lower risk than most CVEs6th percentile — riskier than 6% of all scored CVEsHighest risk

EPSS (Exploit Prediction Scoring System) is a daily probability model maintained by FIRST.org. It estimates the likelihood a CVE will be exploited in production environments within the next 30 days, derived from real-world threat intelligence signals.

How urgent is this, really

GHSA-r73j-pqj5-w3x7 plotted by exploitation likelihood (EPSS) against impact (CVSS). The shaded corner — EPSS 50%+ and CVSS 7.0+ — is where this CVE doesn't sit, though severity or exploitability alone can still warrant action.

Where this sits among everything scored

Of 379,145 CVEs with a current EPSS score, this one falls in the < 10% band (highlighted). Real counts from FIRST.org, not a sample — log-scaled since the landscape is heavily right-skewed.

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

Impact

An attacker can supply a malicious PDF that causes the process to hang indefinitely, consuming 100% CPU and making the application unresponsive.

Patches

Patched version: 12.2.0.

PdfParser (introduced in Pillow 4.2.0) follows Prev pointers in PDF trailers to read cross-reference sections. If a trailer's Prev pointer references an offset that has already been processed — either pointing to itself or forming a longer cycle — the parser enters an infinite loop. Pillow now tracks previously processed trailer offsets and raises an error if a cycle is detected.

Workarounds

Use any version but the affected versions: >= 4.2.0, < 12.2.0

Resources

Affected Packages

1 total 1 fixed
EcosystemPackageVulnerable rangeFix
🐍PyPIpillow≥ 4.2.0&&< 12.2.012.2.0pip install --upgrade 'pillow==12.2.0'

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 12.2.0 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms GHSA-r73j-pqj5-w3x7 is resolved across your whole dependency graph.

  3. Workarounds

    If you can't upgrade right away: gate or disable the affected feature, validate untrusted input at the boundary, and avoid passing attacker-controlled data into the vulnerable path. O3's runtime protection blocks exploitation in production as an interim safeguard until the upgrade lands.

  4. How O3 protects you

    O3 Security's impact-aware SCA analyses which vulnerable code paths your application actually calls, so a match like GHSA-r73j-pqj5-w3x7 can be triaged on real exposure rather than presence alone.

Tailored to GHSA-r73j-pqj5-w3x7. Runtime protection reduces exposure until a permanent patch is applied and verified — it complements patching, it doesn't replace it.

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
ProductFixed inAdvisory
Red Hat AI Inference Server 3.3rhaiis/model-opt-cuda-rhel9:1778244559RHSA-2026:16008
Red Hat AI Inference Server 3.3rhaiis/vllm-rocm-rhel9:1778244531RHSA-2026:16009
Red Hat AI Inference Server 3.3rhaiis/vllm-cuda-rhel9:1778274666RHSA-2026:16030
Red Hat AI Inference Server 3.4rhaii/vllm-spyre-rhel9:1787151840RHSA-2026:57387

Frequently Asked Questions

### Impact An attacker can supply a malicious PDF that causes the process to hang indefinitely, consuming 100% CPU and making the application unresponsive. ### Patches Patched version: 12.2.0. PdfParser (introduced in Pillow 4.2.0) follows Prev pointers in PDF trailers to read cross-reference sections. If a trailer's Prev pointer references an offset that has already been processed — either pointing to itself or forming a longer cycle — the parser enters an infinite loop. Pillow now tracks previously processed trailer offsets and raises an error if a cycle is detected. ### Workarounds Use a
O3 Security · Impact-Aware SCA

Is GHSA-r73j-pqj5-w3x7 in your dependencies?

O3 Security finds GHSA-r73j-pqj5-w3x7 across PyPI dependencies, including transitive ones, and its impact-aware SCA ranks findings by whether your code actually calls the vulnerable path.

GHSA-r73j-pqj5-w3x7: pillow (Medium 5.5) | O3 Security