CVE-2026-82398
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 6.15.0, an attacker can craft a PDF that causes long runtimes when the pypdf/_utils.py function read_until_whitespace reads a stream containing a long run of bytes without whitespace. The function repeatedly performs immutable bytes concatenation in a one-byte loop, causing quadratic processing cost for the long non-whitespace input. This issue is fixed in version 6.15.0.
CVSS
5.3
5.3 (CVSS v3.1)
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:L Severity source: NVD CVSS v3.1 (nvd@nist.gov)
Timeline (UTC)
Published: 2026-08-31 22:17
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 <6.15.0
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/4959848e057e37c218dccad7465259210923faaa
Patch / mitigation: https://github.com/py-pdf/pypdf/pull/3947
Patch / mitigation: https://github.com/py-pdf/pypdf/security/advisories/GHSA-fc8x-2rww-xw9m
References
- https://github.com/py-pdf/pypdf/commit/4959848e057e37c218dccad7465259210923faaa security-advisories@github.com
- https://github.com/py-pdf/pypdf/pull/3947 security-advisories@github.com
- https://github.com/py-pdf/pypdf/releases/tag/6.15.0 security-advisories@github.com
- https://github.com/py-pdf/pypdf/security/advisories/GHSA-fc8x-2rww-xw9m security-advisories@github.com
Data sources
NVD CVE API 2.0 — fetched 2026-11-03 07:34 UTC · record ↗