CVE-2026-27026
mediumpypdf is a free and open-source pure-python PDF library.
Vendor / product: Py-pdf — pypdf
pypdf is a free and open-source pure-python PDF library. Prior to 6.7.1, an attacker who uses this vulnerability can craft a PDF which leads to long runtimes. This requires a malformed /FlateDecode stream, where the byte-by-byte decompression is used. This vulnerability is fixed in 6.7.1.
CVSS
5.5
5.5 (CVSS v3.1)
CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H Severity source: NVD CVSS v3.1 (nvd@nist.gov)
Timeline (UTC)
Published: 2026-02-20 22:16
Modified: 2026-11-02 16:06
NVD status: Analyzed
Last synced 1 day ago
Verified against the source API 2026-11-03 07:34 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
py-pdf / pypdf <6.7.1
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/7905842d833f899f1d3228af7e7467ad80277016
Patch / mitigation: https://github.com/py-pdf/pypdf/pull/3644
Patch / mitigation: https://github.com/py-pdf/pypdf/security/advisories/GHSA-9mvc-8737-8j8h
References
- https://github.com/py-pdf/pypdf/commit/7905842d833f899f1d3228af7e7467ad80277016 security-advisories@github.com
- https://github.com/py-pdf/pypdf/pull/3644 security-advisories@github.com
- https://github.com/py-pdf/pypdf/releases/tag/6.7.1 security-advisories@github.com
- https://github.com/py-pdf/pypdf/security/advisories/GHSA-9mvc-8737-8j8h security-advisories@github.com
Data sources
NVD CVE API 2.0 — fetched 2026-11-03 07:34 UTC · record ↗