CVE-2026-41313 Py Pdf CVE debrief

Who should care

Defenders responsible for maintaining Python environments with the pypdf library should assess exposure and apply the patch or workaround. This includes verifying exposure in inventory, applying the patch or workaround, and monitoring for potential impacts. Defenders should also review compensating controls for exposed systems and check relevant monitoring, detection, and logs for exposed assets.

Why it matters

CVE-2026-41313 is a vulnerability in the pypdf library that can lead to long runtimes when loading a specially crafted PDF file. Defenders should prioritize verifying exposure in their inventory and applying the patch or workaround.

• Potential denial-of-service due to long runtimes
• Need to verify exposure in inventory
• Need to apply patch or workaround
• Potential impact on system performance

Technical summary

The pypdf library is vulnerable to a denial-of-service attack when loading a specially crafted PDF file. The issue is caused by a large trailer `/Size` value in incremental mode, which can lead to long runtimes. This has been fixed in pypdf version 6.10.2. The vulnerability requires loading a PDF with a large trailer `/Size` value in incremental mode, which can cause performance issues. Defenders should prioritize verifying exposure in their inventory and applying the patch or workaround. The fix involves updating to pypdf version 6.10.2 or later.

Defensive priority

Defenders should prioritize verifying exposure in their inventory and applying the patch or workaround.

Recommended defensive actions

• Verify exposure in inventory
• Apply the patch or workaround
• Monitor for potential impacts
• Review compensating controls for exposed systems
• Check relevant monitoring, detection, and logs for exposed assets
• Track exceptions and retest remediated assets
• Review the supplied official advisory or CVE record to validate affected scope, severity, and vendor guidance

Evidence notes

The vulnerability is described in the CVE record and NVD entry. The fix is available in pypdf version 6.10.2. Defenders should verify exposure in their inventory and apply the patch or workaround. The CVE record was published on 2026-04-22T22:16:32.220Z and has not been modified since then. The NVD entry provides additional details on the vulnerability. The patch details are available in the referenced sources.

Sources and references

Methodology and review provenance

AI-assisted synthesis based on stored public vulnerability evidence. System validation, approval state, and publication status do not by themselves establish human review of this revision. PatchSiren helps prioritize defensive review and does not prove exposure or remediation on any system.