CVE-2026-54531: CWE-835: Loop with Unreachable Exit Condition ('Infinite Loop') in py-pdf pypdf
CVE-2026-54531 is a medium severity vulnerability in the pypdf library prior to version 6.13.0. It involves an infinite loop triggered when merging a PDF file containing outlines into a writer. This flaw allows an attacker to craft a malicious PDF that causes the library to enter a loop with no exit condition. The issue is fixed in pypdf version 6.13.0.
AI Analysis
Technical Summary
The vulnerability identified as CVE-2026-54531 affects pypdf, a pure-Python PDF library. Prior to version 6.13.0, the library contains a loop with an unreachable exit condition (CWE-835) that can be triggered by merging a PDF file with outlines into a writer object. This results in an infinite loop, potentially causing denial of service by hanging the processing thread. The vulnerability has a CVSS 4.0 base score of 6.9, indicating medium severity, with local attack vector and no privileges or user interaction required. The issue is resolved in version 6.13.0.
Potential Impact
An attacker who can supply a crafted PDF file with outlines to be merged can cause the pypdf library to enter an infinite loop, leading to denial of service conditions such as application hang or resource exhaustion. There is no indication of code execution or data leakage from this vulnerability.
Mitigation Recommendations
Upgrade pypdf to version 6.13.0 or later, where this infinite loop vulnerability is fixed. No other mitigation or temporary workaround is indicated. Patch status is confirmed fixed in 6.13.0.
CVE-2026-54531: CWE-835: Loop with Unreachable Exit Condition ('Infinite Loop') in py-pdf pypdf
Description
CVE-2026-54531 is a medium severity vulnerability in the pypdf library prior to version 6.13.0. It involves an infinite loop triggered when merging a PDF file containing outlines into a writer. This flaw allows an attacker to craft a malicious PDF that causes the library to enter a loop with no exit condition. The issue is fixed in pypdf version 6.13.0.
CVSS v4.0
Score 6.9medium
Affected software
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Weaknesses
AI-Powered Analysis
Machine-generated threat intelligence
Technical Analysis
The vulnerability identified as CVE-2026-54531 affects pypdf, a pure-Python PDF library. Prior to version 6.13.0, the library contains a loop with an unreachable exit condition (CWE-835) that can be triggered by merging a PDF file with outlines into a writer object. This results in an infinite loop, potentially causing denial of service by hanging the processing thread. The vulnerability has a CVSS 4.0 base score of 6.9, indicating medium severity, with local attack vector and no privileges or user interaction required. The issue is resolved in version 6.13.0.
Potential Impact
An attacker who can supply a crafted PDF file with outlines to be merged can cause the pypdf library to enter an infinite loop, leading to denial of service conditions such as application hang or resource exhaustion. There is no indication of code execution or data leakage from this vulnerability.
Mitigation Recommendations
Upgrade pypdf to version 6.13.0 or later, where this infinite loop vulnerability is fixed. No other mitigation or temporary workaround is indicated. Patch status is confirmed fixed in 6.13.0.
Technical Details
- Data Version
- 5.2
- Assigner Short Name
- GitHub_M
- Date Reserved
- 2026-06-15T18:40:01.651Z
- Cvss Version
- 4.0
- State
- PUBLISHED
- Remediation Level
- null
Threat ID: 6a39a0f5eed863c81e6b01fa
Added to database: 06/22/2026, 20:54:13 UTC
Last enriched: 06/22/2026, 21:09:27 UTC
Last updated: 06/22/2026, 23:37:20 UTC
Views: 8
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