CVE-2026-82398CWE-407

CVE-2026-82398

Medium · published September 1, 2026

CVSS v3.1
5.3
EPSS
1%
Percentile
43.6
In the wild
Unconfirmed
What it is

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.

The record
Technical detail
CVSS v3.1
5.3 · MEDIUM
Vector
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:L
CVSS v4.0
6.9 · CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:L/SC:N/SI:N/SA:N
EPSS
0.00524 · 43.6th percentile
Weakness
CWE-407 · Inefficient Algorithmic Complexity
Published
2026-09-01T02:17Z
Affected products (1)
ProductVersionsFixed in
pypdf_project/pypdf< 6.15.06.15.0
References (4)
https://github.com/py-pdf/pypdf/commit/4959848e057e37c218dccad7465259210923faaa · [email protected]https://github.com/py-pdf/pypdf/pull/3947 · [email protected]https://github.com/py-pdf/pypdf/releases/tag/6.15.0 · [email protected]https://github.com/py-pdf/pypdf/security/advisories/GHSA-fc8x-2rww-xw9m · [email protected]
EPSS history
Timeline
  • 02 SEP 03:39Z
    EPSS moved — → 0%
    epss
  • 31 AUG 21:41Z
    pypdf: Inefficient handling of non-whitespace inputs in read_until_whitespace
    cvelistv5