CVE-2023-36807: py-pdf pypdf Infinite Loop

Vulnerability summary

CVE-2023-36807 is a medium (CVSS 6.5) Infinite Loop vulnerability in py-pdf pypdf. EPSS estimates a 0.57% chance of exploitation in the next 30 days, higher than 46.5% of scored vulnerabilities. 1 public exploit is recorded.

Timeline

1. 30-06-2023
   PublishedVulnerability first disclosed.
2. 06-11-2024
   Last modifiedVulnerability information updated.

Description

pypdf is a pure-python PDF library capable of splitting, merging, cropping, and transforming the pages of PDF files. In version 2.10.5 an attacker who uses this vulnerability can craft a PDF which leads to an infinite loop. This infinite loop blocks the current process and can utilize a single core of the CPU by 100%. It does not affect memory usage. That is, for example, the case if the user extracted metadata from such a malformed PDF. Versions prior to 2.10.5 throw an error, but do not hang forever. This issue was fixed with https://github.com/py-pdf/pypdf/pull/1331 which has been included in release 2.10.6. Users are advised to upgrade. Users unable to upgrade should modify `PyPDF2/generic/_data_structures.py::read_object` to an an error throwing case. See GHSA-hm9v-vj3r-r55m for details.

• CWE-835Loop with Unreachable Exit Condition ('Infinite Loop')The product contains an iteration or loop with an exit condition that cannot be reached, i.e., an infinite loop.