CVE-2026-82398
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.
Scoring
- Severity
- MEDIUM
- CVSS base score
- 6.9
- CVSS vector
- 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 probability
- 0.30%
- CWE
- CWE-407
- Published
- 2026-08-31
- Last modified
- 2026-09-01
Affected products
- py-pdf pypdf
Weakness type
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