CVE-2026-40260 — pypdf
Fix: py-pdf/pypdf@b15a374CVE-2026-40260 is a CWE-776 vulnerability in pypdf. A fix is available for pypdf — see the affected versions and patch details below.
pypdf: Manipulated XMP metadata entity declarations can exhaust RAM
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 CVE-2026-40260.
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
pypdf is a free and open-source pure-python PDF library. In versions prior to 6.10.0, manipulated XMP metadata entity declarations can exhaust RAM. An attacker who exploits this vulnerability can craft a PDF which leads to large memory usage. This requires parsing the XMP metadata. This issue has been fixed in version 6.10.0.
Affected Packages
| Ecosystem | Package | Vulnerable range | Fix |
|---|---|---|---|
| 🐍PyPI | pypdf | all versions | 6.10.0pip install --upgrade 'pypdf==6.10.0' |
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 6.10.0 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms CVE-2026-40260 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.
Red Hat rates this vulnerability as Moderate impact with a CVSS score of 6.5. The vulnerable code is in pypdf's XMP metadata parser, which only runs when application code calls reader.xmp_metadata. Opening a PDF or extracting text does not trigger it. Red Hat products ship pypdf through LlamaIndex, which calls…
Do not call reader.xmp_metadata on untrusted PDF input. The standard PDF metadata property (reader.metadata) uses a separate code path and is not affected. If you must process XMP metadata from untrusted PDFs, set memory limits on the process or container to contain the impact of a potential denial of service.Source: Red Hat security advisory for CVE-2026-40260 (CC BY 4.0)
Frequently Asked Questions
Is CVE-2026-40260 in your dependencies?
Find it across PyPI, including transitive dependencies.