py-pdf pypdf up to 6.9.0 PDF resource consumption

Summaryinfo

A vulnerability has been found in py-pdf pypdf up to 6.9.0 and classified as problematic. This vulnerability affects unknown code of the component PDF Handler. Performing a manipulation results in resource consumption. This vulnerability is reported as CVE-2026-33123. The attack is possible to be carried out remotely. No exploit exists. The affected component should be upgraded.

Detailsinfo

A vulnerability, which was classified as problematic, was found in py-pdf pypdf up to 6.9.0. This affects an unknown part of the component PDF Handler. The manipulation with an unknown input leads to a resource consumption vulnerability. CWE is classifying the issue as CWE-400. The product does not properly control the allocation and maintenance of a limited resource, thereby enabling an actor to influence the amount of resources consumed, eventually leading to the exhaustion of available resources. This is going to have an impact on availability. The summary by CVE is:

pypdf is a free and open-source pure-python PDF library. Versions prior to 6.9.1 allow an attacker to craft a malicious PDF which leads to long runtimes and/or large memory usage. Exploitation requires accessing an array-based stream with many entries. This issue has been fixed in version 6.9.1.

It is possible to read the advisory at github.com. This vulnerability is uniquely identified as CVE-2026-33123 since 03/17/2026. The exploitability is told to be easy. It is possible to initiate the attack remotely. No form of authentication is needed for exploitation. The technical details are unknown and an exploit is not publicly available. The attack technique deployed by this issue is T1499 according to MITRE ATT&CK.

The vulnerability scanner Nessus provides a plugin with the ID 303237 (Linux Distros Unpatched Vulnerability : CVE-2026-33123), which helps to determine the existence of the flaw in a target environment.

Upgrading to version 6.9.1 eliminates this vulnerability.

The vulnerability is also documented in the vulnerability database at Tenable (303237). Be aware that VulDB is the high quality source for vulnerability data.

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
• 6.9.0

Website

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

CPE 2.3info

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CPE 2.2info

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Entryinfo

Be aware that VulDB is the high quality source for vulnerability data.

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