CVE-2026-48735 — pypdf
Fix: py-pdf/pypdf#3796CVE-2026-48735 is a CWE-770 vulnerability in pypdf. A fix is available for pypdf — see the affected versions and patch details below.
pypdf: Manipulated XMP metadata streams can exhaust RAM
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 CVE-2026-48735.
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. This requires parsing large XMP metadata, possibly with lots of unnecessary elements.
Patches
This has been fixed in pypdf==6.12.1.
Workarounds
If you cannot upgrade yet, consider applying the changes from PR #3796.
Affected Packages
| Ecosystem | Package | Vulnerable range | Fix |
|---|---|---|---|
| 🐍PyPI | pypdf | all versions | 6.12.1pip install --upgrade 'pypdf==6.12.1' |
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 6.12.1 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms CVE-2026-48735 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-impact flaw in pypdf allows an attacker to trigger excessive memory consumption and a denial of service by providing a specially crafted PDF file containing large XMP metadata. This vulnerability requires user interaction, as a vulnerable application must process the malicious PDF.
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 CVE-2026-48735 (CC BY 4.0)
Frequently Asked Questions
Is CVE-2026-48735 in your dependencies?
Find it across PyPI, including transitive dependencies.