CVE-2026-82398: pypdf: Inefficient handling of non-whitespace inputs in read_until_whitespace

September 2, 2026

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.

References

github.com/advisories/GHSA-fc8x-2rww-xw9m
github.com/py-pdf/pypdf/commit/4959848e057e37c218dccad7465259210923faaa
github.com/py-pdf/pypdf/pull/3947
github.com/py-pdf/pypdf/releases/tag/6.15.0
github.com/py-pdf/pypdf/security/advisories/GHSA-fc8x-2rww-xw9m
nvd.nist.gov/vuln/detail/CVE-2026-82398

Code Behaviors & Features

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