pypdf: Manipulated FlateDecode predictor parameters can exhaust RAMGHSA-7gw9-cf7v-778f
MEDIUMFix: py-pdf/pypdf#3734GHSA-7gw9-cf7v-778f is a medium-severity (CVSS 6.5) CWE-789 vulnerability in pypdf. A fix is available for pypdf — see the affected versions and patch details below.
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-7gw9-cf7v-778f.
EPSS Exploitation Probability
Probability of exploitation in the next 30 days, from FIRST.org EPSS.
How urgent is this, really
Where this sits among everything scored
Real-World Exposure
pypdfReal-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 who uses this vulnerability can craft a PDF which leads to the RAM being exhausted. This requires accessing a stream compressed using /FlateDecode with a /Predictor unequal 1 and large predictor parameters.
Patches
This has been fixed in pypdf==6.10.2.
Workarounds
If you cannot upgrade yet, consider applying the changes from PR #3734.
Affected Packages
| Ecosystem | Package | Vulnerable range | Fix |
|---|---|---|---|
| 🐍PyPI | pypdf | all versions | 6.10.2pip install --upgrade 'pypdf==6.10.2' |
Affected Products
pypdfpy-pdfDetection & mitigation playbook
Open-source dependencyDetect
Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for pypdf, including transitive dependencies — a direct dependency you never call can still pull in a vulnerable version.
Fix
Update pypdf to 6.10.2 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms GHSA-7gw9-cf7v-778f is resolved across your whole dependency graph.
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.
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.
Mitigation for this issue is either not available or the currently available options do not meet the Red Hat Product Security criteria comprising ease of use and deployment, applicability to widespread installation base, or stability.Source: Red Hat security advisory for GHSA-7gw9-cf7v-778f (CC BY 4.0)
Frequently Asked Questions
Is GHSA-7gw9-cf7v-778f in your dependencies?
Find it across PyPI, including transitive dependencies.