CVE-2026-33123
MEDIUM6.5EPSS 0.01%pypdf has inefficient decoding of array-based streams
Published: 3/18/2026Modified: 4/28/2026
Description
pypdf is a free and open-source pure-python PDF library. Versions prior to 6.9.1 allow an attacker to craft a malicious PDF which leads to long runtimes and/or large memory usage. Exploitation requires accessing an array-based stream with many entries. This issue has been fixed in version 6.9.1.
Affected packages (3)
- Debian/pypdffrom 0
- Debian/pypdf2from 0
- PyPI/pypdffrom 0, < 6.9.1
CVSS scores
| Source | Version | Severity | Vector |
|---|---|---|---|
| osv | CVSS 4.0 | — | CVSS:4.0/AV:L/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:L/SC:N/SI:N/SA:N |
| osv | CVSS 3.1 | MEDIUM6.5 | CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:N/I:N/A:H |
References (6)
- ADVISORYhttps://nvd.nist.gov/vuln/detail/CVE-2026-33123
- ADVISORYhttps://security-tracker.debian.org/tracker/CVE-2026-33123
- PATCHhttps://github.com/py-pdf/pypdf
- WEBhttps://github.com/py-pdf/pypdf/pull/3686
- WEBhttps://github.com/py-pdf/pypdf/releases/tag/6.9.1
- WEBhttps://github.com/py-pdf/pypdf/security/advisories/GHSA-qpxp-75px-xjcp