Vulnerability in Py-Pdf Pypdf
CVE-2026-41313
pypdf is a free and open-source pure-python PDF library. An attacker who uses a vulnerability present in versions prior to 6.10.2 can craft a PDF which leads to long runtimes. This requires loading a PDF with a large trailer `/Size` value in incremental mode. This has been fixed in pypdf 6.10.2. As a workaround, one may apply the changes from the patch manually.
Published · last modified .
CVSS v3 metric
CVSS v3 base score 6.5 (Medium). Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:N/I:N/A:H.
EPSS exploit prediction
EPSS: 0.004 (30.9th percentile), scored .
Very low probability of exploitation in the next 30 days; routine patching cadence is appropriate. 31st percentile — 30.9% of CVEs in the catalogue have a lower EPSS than this one. How to read EPSS.
EPSS over last 30 days · oldest: 0.002 · newest: 0.004 · change: +0.002
Affected products
- Py-Pdf Pypdf — versions < 6.10.2
- Pypdf Project
Weakness classification (CWE)
References
- github.com/py-pdf/pypdf/security/advisories/GHSA-4pxv-j86v-mhcw (Patch, Vendor Advisory)
- github.com/py-pdf/pypdf/pull/3735 (Patch, Issue Tracking)
- github.com/py-pdf/pypdf/commit/c50a0104cf083356f7c7f5d61410466a57f5c88a (Patch)
- github.com/py-pdf/pypdf/releases/tag/6.10.2 (Release Notes)
Frequently asked questions
- What is CVE-2026-41313?
- CVE-2026-41313 is a medium-severity vulnerability in Py-Pdf Pypdf, classified under Excessive Iteration. CVSS score: 6.5/10. Published 2026-04-22.
- How severe is CVE-2026-41313?
- Medium severity. CVSS v3 base score is 6.5 out of 10.