pypdf: Possible infinite loop in PdfWriter.find_outline_item
Impact
An attacker who uses this vulnerability can craft a PDF which leads to an infinite loop. This requires calling find_outline_item on a PdfWriter.
Patches
This has been fixed in pypdf==6.20.1.).
Workarounds
If you cannot upgrade yet, consider applying the changes from PR #4188.).
What to do
Upgrade to pypdf==6.20.1.) or apply the changes from PR #4188.).
Affected software
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| Platform | Package | Vulnerable versions | Fixed in |
|---|---|---|---|
| Python (PyPI) | pypdf | < 6.20.1 | 6.20.1 |
References
- CVSS vector
CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:P/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N- Weakness (CWE)
CWE-835- Platform
- Python (PyPI)
- Package
pypdf- Disclosed
- 21.10.2026
- Updated
- 21.10.2026 19:23
Sources and licenses · Edited or translated by DockRay; source rights and applicable licenses are retained.
OSV / GitHub Advisory Database - GHSA-qfv9-64jg-mh7p - CC BY 4.0
Vulnerability history: pypdf
All published vulnerabilities of this package (Python (PyPI)), newest first. Shows whether this is a one-off slip or a package that needs watching.
- Total entries
- 55
- First → latest
- 06.2023 10.2026
- Without a fix
- 0
- Exploited in attacks
- 0
Severity breakdown
- High 10
- Medium 42
- Low 3
Disclosures per year
- 2023: 2
- 2024: 0
- 2025: 4
- 2026: 49
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pypdf: Possible infinite loop in PdfWriter.find_outline_item this entry
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