CVE-2026-113793 py-pdf CVE debrief

Who should care

Defenders responsible for processing PDFs using the pypdf library should be aware of this vulnerability and take steps to mitigate it. This includes upgrading to the fixed version or applying the changes from PR #4188. Defenders should also review the source item and the official advisory for more information on the vulnerability and the available fixes. Additionally, defenders should prioritize upgrading to the fixed version to prevent potential infinite

Why it matters

CVE-2026-113793 is a vulnerability in the pypdf library that can cause an infinite loop when removing tree items from a PDF. Defenders should prioritize upgrading to pypdf version 6.20.1 or applying the changes from PR #4188 to prevent potential infinite loops when processing PDFs.

• Potential denial of service due to infinite loop
• Increased risk of PDF processing failures

Technical summary

The pypdf library is vulnerable to an infinite loop when removing tree items from a PDF. This can be exploited by crafting a malicious PDF that triggers this issue. The vulnerability is related to the library's handling of tree items in PDFs, which can lead to an infinite loop if not properly mitigated. Defenders should prioritize upgrading to the fixed version to prevent potential infinite loops when processing PDFs. The vulnerability can be mitigated by upgrading to pypdf version 6.20.1 or applying the changes from PR #4188.

Defensive priority

Defenders should prioritize upgrading to pypdf version 6.20.1 or applying the changes from PR #4188 to prevent potential infinite loops when processing PDFs.

Recommended defensive actions

• Upgrade to pypdf version 6.20.1
• Apply changes from PR #4188 as a workaround
• Review PDF processing code for potential infinite loops
• Confirm whether affected product deployments exist in managed environments and assign an owner for follow-up
• Review the supplied official advisory or CVE record to validate affected scope, severity, and vendor guidance
• Plan vendor-supported updates or mitigations through normal change control where exposure is confirmed
• Track exceptions, retest remediated assets, and close the item only after evidence is documented.

Evidence notes

The vulnerability is described in the source item as a possible infinite loop when removing tree items from a PDF. The fix is available in pypdf version 6.20.1. The source item provides a detailed description of the issue, including the affected versions and the fixed version. Defenders should review the source item and the official advisory for more information on the vulnerability and the available fixes.

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.