CVE-2026-84309
mediumpypdf is a free and open-source pure-python PDF library.
Vendor / product: Pypdf Project — pypdf
pypdf is a free and open-source pure-python PDF library. Prior to 6.16.0, an attacker can craft a PDF whose cyclic tree structure causes pypdf/generic/_data_structures.py TreeObject.insert_child to follow /Next links indefinitely when a writing code path inserts a child, producing an infinite loop. This issue is fixed in version 6.16.0.
CVSS
5.5
5.5 (CVSS v3.1)
CVSS:3.1/AV:L/AC:L/PR:N/UI:R/S:U/C:N/I:N/A:H Severity source: NVD CVSS v3.1 (nvd@nist.gov)
Timeline (UTC)
Published: 2026-09-01 20:17
Modified: 2026-10-05 17:42
NVD status: Analyzed
Last synced 1 day ago
Verified against the source API 2026-10-27 06:50 UTC
Exploitation
Not listed in CISA KEV (as of last catalog sync)
Absence from KEV does not mean a CVE is not exploited. Exploitation status: unknown (no authoritative evidence in our sources).
Affected products
pypdf_project / pypdf <6.16.0
Weakness classification (CWE)
Source: NVD / CISA. “NVD-CWE-Other” and “NVD-CWE-noinfo” mean NVD could not assign a specific weakness.
Mitigation & advisories
Patch / mitigation: https://github.com/py-pdf/pypdf/commit/c9ba557d565d57c53a0b3a0be06c0a4c29b0559b
Patch / mitigation: https://github.com/py-pdf/pypdf/pull/3964
Patch / mitigation: https://github.com/py-pdf/pypdf/security/advisories/GHSA-jp53-mhqp-8xcg
References
- https://github.com/py-pdf/pypdf/commit/c9ba557d565d57c53a0b3a0be06c0a4c29b0559b security-advisories@github.com
- https://github.com/py-pdf/pypdf/pull/3964 security-advisories@github.com
- https://github.com/py-pdf/pypdf/releases/tag/6.16.0 security-advisories@github.com
- https://github.com/py-pdf/pypdf/security/advisories/GHSA-jp53-mhqp-8xcg security-advisories@github.com
Data sources
NVD CVE API 2.0 — fetched 2026-10-27 06:50 UTC · record ↗