CVE-2026-119205
High
Description
pypdf is a free and open-source pure-python PDF library. Prior to 6.21.4, pypdf can enter an infinite loop when cloning or duplicating a crafted cyclic DictionaryObject. Clone traversal checked generated destination references rather than the original source references, allowing some source cycles to evade the visited-object check. This issue is fixed in version 6.21.4.
SeverityHigh
CVSS5.5
Exploit probability—
ProductPy-pdf Pypdf
PublishedOct 29, 2026
First seenNov 4, 2026
Weakness typeCWE-835CWE-835
How to fix
Update
- py-pdf pypdf6.21.4 or later
- pypdf6.21.4 or later
Affected products
| Product | Affected versions | Fixed in |
|---|---|---|
| py-pdf pypdf | v < 6.21.4 | 6.21.4 |
| pypdfPyPI | v < 6.21.4 | 6.21.4 |
Check your version
Choose the product and enter the version you run to see whether it falls in the affected range.
In the Intelligence 360 plan
Attack Surface Management
See the assets tied to your domains, the technologies they run and known vulnerabilities in one list.