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7.3
pypdf: Infinite Loop in Processing PDF Outlines
CVE-2026-27024
GHSA-996q-pr4m-cvgq
CVE-2026-27024
Summary
An attacker can create a malicious PDF that causes pypdf to run indefinitely. This could lead to a denial-of-service (DoS) situation. Update to version 6.7.1 or later to fix this issue.
What to do
- Update pypdf to version 6.7.1.
Affected software
| Vendor | Product | Affected versions | Fix available |
|---|---|---|---|
| – | pypdf | <= 6.7.1 | 6.7.1 |
| pypdf_project | pypdf | <= 6.7.1 | – |
Original title
pypdf has a possible infinite loop when processing TreeObject
Original description
pypdf is a free and open-source pure-python PDF library. Prior to 6.7.1, an attacker who uses this vulnerability can craft a PDF which leads to an infinite loop. This requires accessing the children of a TreeObject, for example as part of outlines. This vulnerability is fixed in 6.7.1.
nvd CVSS3.1
5.5
nvd CVSS4.0
6.9
Vulnerability type
CWE-835
- https://nvd.nist.gov/vuln/detail/CVE-2026-27024
- https://github.com/advisories/GHSA-996q-pr4m-cvgq
- https://github.com/py-pdf/pypdf/commit/bd2f6d052fe5941e85e37082c2a43453d48d1295 Patch
- https://github.com/py-pdf/pypdf/pull/3645 Issue Tracking Patch
- https://github.com/py-pdf/pypdf/releases/tag/6.7.1 Product Release Notes
- https://github.com/py-pdf/pypdf/security/advisories/GHSA-996q-pr4m-cvgq Patch Vendor Advisory
- https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/27xxx/CVE-2026-27024... Vendor Advisory
Published: 20 Feb 2026 · Updated: 12 Mar 2026 · First seen: 6 Mar 2026