CVE-2026-71870: pypdf: Possible large memory usage for large /ToUnicode streams

August 7, 2026

An attacker who uses this vulnerability can craft a PDF which leads to large memory consumption. This requires parsing the /ToUnicode entry of a font with unusually large values, for example during text extraction.

References

github.com/advisories/GHSA-fp3f-mc75-235c
github.com/py-pdf/pypdf/commit/afba8080e19d29a3c256a742b340995e695b35aa
github.com/py-pdf/pypdf/pull/3944
github.com/py-pdf/pypdf/releases/tag/6.15.0
github.com/py-pdf/pypdf/security/advisories/GHSA-fp3f-mc75-235c
nvd.nist.gov/vuln/detail/CVE-2026-71870

Code Behaviors & Features

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