GHSA-7gw9-cf7v-778f: pypdf: Manipulated FlateDecode predictor parameters can exhaust RAM

April 16, 2026

An attacker who uses this vulnerability can craft a PDF which leads to the RAM being exhausted. This requires accessing a stream compressed using /FlateDecode with a /Predictor unequal 1 and large predictor parameters.

References

github.com/advisories/GHSA-7gw9-cf7v-778f
github.com/py-pdf/pypdf
github.com/py-pdf/pypdf/pull/3734
github.com/py-pdf/pypdf/releases/tag/6.10.2
github.com/py-pdf/pypdf/security/advisories/GHSA-7gw9-cf7v-778f

Code Behaviors & Features

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