pypdf: Missing stream length values ignore defined limitsGHSA-jm82-fx9c-mx94
Fix: py-pdf/pypdf#3871GHSA-jm82-fx9c-mx94 is a Uncontrolled Resource Consumption 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 assesses this as automatable — exploitation doesn’t require manual, per-target effort, which raises the odds of mass scanning and opportunistic attacks.
- 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-jm82-fx9c-mx94.
EPSS Exploitation Probability
Probability of exploitation in the next 30 days, from FIRST.org EPSS.
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 large memory usage, as MAX_DECLARED_STREAM_LENGTH is sometimes ignored. This requires parsing a content stream without a /Length value.
Patches
This has been fixed in pypdf==6.13.3.
Workarounds
If you cannot upgrade yet, consider applying the changes from PR #3871.
Affected Packages
| Ecosystem | Package | Vulnerable range | Fix |
|---|---|---|---|
| 🐍PyPI | pypdf | all versions | 6.13.3pip install --upgrade 'pypdf==6.13.3' |
Affected Products
pypdfpypdf_projectDetection & 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 6.13.3 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms GHSA-jm82-fx9c-mx94 is resolved across your whole dependency graph.
Workarounds
Cap what an attacker can consume: apply request size, rate and timeout limits in front of the affected component, and run it with memory and CPU limits so exhaustion degrades one worker rather than the whole service.
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.
This Moderate flaw in pypdf can lead to a Denial of Service (DoS) due to uncontrolled memory consumption when processing a specially crafted PDF file. The vulnerability arises from the library's failure to properly enforce stream length limits in certain scenarios, allowing an attacker to exhaust system resources. Red…
To mitigate this issue, Red Hat recommends avoiding the processing of untrusted PDF files with applications utilizing the pypdf library. Additionally, deploying applications that handle PDF content within a sandboxed environment can limit the potential impact of successful exploitation.Source: Red Hat security advisory for GHSA-jm82-fx9c-mx94 (CC BY 4.0)
Frequently Asked Questions
Is GHSA-jm82-fx9c-mx94 in your dependencies?
Find it across PyPI, including transitive dependencies.