Vulnerability in Py-Pdf Pypdf
CVE-2026-24688
pypdf is a free and open-source pure-python PDF library. An attacker who uses an infinite loop vulnerability that is present in versions prior to 6.6.2 can craft a PDF which leads to an infinite loop. This requires accessing the outlines/bookmarks. This has been fixed in pypdf 6.6.2. If projects cannot upgrade yet, consider applying the changes from PR #3610 manually.
Published · last modified .
CVSS v3 metric
CVSS v3 base score 4.3 (Medium). Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:N/I:N/A:L.
EPSS exploit prediction
EPSS: 0.005 (36.7th percentile), scored .
Very low probability of exploitation in the next 30 days; routine patching cadence is appropriate. 37th percentile — 36.7% of CVEs in the catalogue have a lower EPSS than this one. How to read EPSS.
EPSS over last 30 days · oldest: 0.004 · newest: 0.005 · change: +0.000
Affected products
- Py-Pdf Pypdf — versions < 6.6.2
- Pypdf Project
Weakness classification (CWE)
Public proof-of-concept exploits
References
- github.com/py-pdf/pypdf/security/advisories/GHSA-2q4j-m29v-hq73 (Vendor Advisory)
- github.com/py-pdf/pypdf/pull/3610 (Issue Tracking)
- github.com/py-pdf/pypdf/commit/b1282f8dcdc1a7b41ceab6740ffddfdf31b1fec1 (Patch)
- github.com/py-pdf/pypdf/releases/tag/6.6.2 (Product, Release Notes)
Frequently asked questions
- What is CVE-2026-24688?
- CVE-2026-24688 is a medium-severity vulnerability in Py-Pdf Pypdf, classified under Loop with Unreachable Exit Condition (Infinite Loop). CVSS score: 4.3/10. Published 2026-01-27.
- How severe is CVE-2026-24688?
- Medium severity. CVSS v3 base score is 4.3 out of 10.
- Is CVE-2026-24688 known to be exploited?
- 2 public proof-of-concept repositories are indexed. Not currently listed in the CISA KEV catalog.