Vulnerability in Py-Pdf Pypdf
CVE-2026-48156
pypdf is a free and open-source pure-python PDF library. Prior to 6.12.0, an attacker who uses this vulnerability can craft a PDF which leads to long runtimes. This requires cross-reference streams with /W [0 0 0] values and large /Size values. This vulnerability is fixed in 6.12.0.
Published · last modified .
CVSS v3 metric
CVSS v3 base score 3.3 (Low). Vector: CVSS:3.1/AV:L/AC:L/PR:N/UI:R/S:U/C:N/I:N/A:L.
EPSS exploit prediction
EPSS: 0.002 (6.2th percentile), scored .
Very low probability of exploitation in the next 30 days; routine patching cadence is appropriate. 6th percentile — 6.2% of CVEs in the catalogue have a lower EPSS than this one. How to read EPSS.
EPSS over last 30 days · oldest: 0.001 · newest: 0.002 · change: +0.000
Affected products
- Py-Pdf Pypdf — versions < 6.12.0
- Pypdf Project
Weakness classification (CWE)
References
- github.com/py-pdf/pypdf/security/advisories/GHSA-248m-82v9-q6g6 (Patch, Vendor Advisory)
- github.com/py-pdf/pypdf/pull/3791 (Patch, Issue Tracking)
- github.com/py-pdf/pypdf/releases/tag/6.12.0 (Release Notes)
Frequently asked questions
- What is CVE-2026-48156?
- CVE-2026-48156 is a low-severity vulnerability in Py-Pdf Pypdf, classified under Excessive Iteration. CVSS score: 3.3/10. Published 2026-05-28.
- How severe is CVE-2026-48156?
- Low severity. CVSS v3 base score is 3.3 out of 10.