pypdf: Inefficient decoding of FlateDecode PNG predictor streams

When

2026-06-16 13:46 UTC

Where

Global (internet)

Category

cyber_advisory · pip

### Impact An attacker who uses this vulnerability can craft a PDF which leads to long runtimes. This requires accessing a stream which uses the `/FlateDecode` filter with a PNG predictor. ### Patches This has been fixed in [pypdf==6.12.2](https://github.com/py-pdf/pypdf/releases/tag/6.12.2). ### Workarounds If you cannot upgrade yet, consider applying the changes from PR [#3806](https://github.com/py-pdf/pypdf/pull/3806).

Sources

• GitHub Advisory Database ↗ · first seen 2026-06-16 13:46 UTC

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Correlated events

Computed by the Defaxon correlation engine — linked by shared actors, co-location, and temporal proximity. Scored hypotheses, never causal claims.

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