pypdf is a free and open-source pure-python PDF library. Prior to 6.21.3, pypdf can consume excessive memory when strict mode loads a crafted invalid PDF dictionary. Nested parsing failures add repeated exception text to newly raised errors, allowing a small malformed dictionary to amplify into very large error messages. This issue is fixed in version 6.21.3.
CVE-2026-119207
CVSS base score
5.5 (v3.1)
Severity
MEDIUM
Attack vector
Local
Weakness
CWE-400, CWE-405
Last modified
November 2, 2026
CVSS vector
CVSS:3.1/AV:L/AC:L/PR:N/UI:R/S:U/C:N/I:N/A:H
Affected products
py-pdf pypdf
References
- github.com Patch
- github.com Patch
- github.com Release Notes
- github.com Patch, Vendor Advisory