py-pdf pypdf up to 6.15.x TreeObject _data_structures.py TreeObject.insert_child infinite loop

Summaryinfo

A vulnerability, which was classified as problematic, was found in py-pdf pypdf up to 6.15.x. The impacted element is the function TreeObject.insert_child of the file pypdf/generic/_data_structures.py of the component TreeObject. Such manipulation leads to infinite loop. This vulnerability is referenced as CVE-2026-84309. It is possible to launch the attack remotely. No exploit is available.

Detailsinfo

A vulnerability, which was classified as problematic, has been found in py-pdf pypdf up to 6.15.x. Affected by this issue is the function TreeObject.insert_child of the file pypdf/generic/_data_structures.py of the component TreeObject. The manipulation with an unknown input leads to a infinite loop vulnerability. Using CWE to declare the problem leads to CWE-835. The product contains an iteration or loop with an exit condition that cannot be reached, i.e., an infinite loop. Impacted is availability. CVE summarizes:

pypdf is a free and open-source pure-python PDF library. Prior to 6.16.0, an attacker can craft a PDF whose cyclic tree structure causes pypdf/generic/_data_structures.py TreeObject.insert_child to follow /Next links indefinitely when a writing code path inserts a child, producing an infinite loop. This issue is fixed in version 6.16.0.

The advisory is available at github.com. This vulnerability is handled as CVE-2026-84309 since 09/01/2026. The exploitation is known to be easy. The attack may be launched remotely. No form of authentication is required for exploitation. Successful exploitation requires user interaction by the victim. Technical details are known, but there is no available exploit. This vulnerability is assigned to T1499 by the MITRE ATT&CK project.

Upgrading to version 6.16.0 eliminates this vulnerability.

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Productinfo

Vendor

• py-pdf

Name

• pypdf

Version

• 6.0
• 6.1
• 6.2
• 6.3
• 6.4
• 6.5
• 6.6
• 6.7
• 6.8
• 6.9
• 6.10
• 6.11
• 6.12
• 6.13
• 6.14
• 6.15

Website

• Product: https://github.com/py-pdf/pypdf/

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