In short
- CVE-2026-82398 is a MEDIUM (CVSS 5.3) vulnerability affecting pypdf, pypdf (pypdf project).
- Chance of exploitation in the next 30 days (EPSS): 0.52%, higher than 44.4% of all vulnerabilities.
- Fix: update to 6.15.0 or later.
| Package | Affected versions | Patched versions |
|---|
| pypdf PyPI | < 6.15.0
| 6.15.0
|
| pypdf | < 6.15.0
| 6.15.0
|
Description
Impact
An attacker who uses this vulnerability can craft a PDF which leads to long runtimes. This requires a call to read_until_whitespace with an input which does not have whitespace for a long time.
Patches
This has been fixed in pypdf==6.15.0.
Workarounds
If you cannot upgrade yet, consider applying the changes from PR #3947.
NVD description
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.
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