CVE-2026-102998: pypdf: Possible long runtimes when generating appearance streams

October 1, 2026

An attacker who uses this vulnerability can craft a PDF which leads to long runtimes. This requires updating form field values with flattening enabled, which triggers appearance stream generation.

References

github.com/advisories/GHSA-php9-fj8v-98fj
github.com/py-pdf/pypdf/commit/959467a9b95be83e2dc5ae873ece5f371263ede7
github.com/py-pdf/pypdf/pull/4087
github.com/py-pdf/pypdf/releases/tag/6.19.0
github.com/py-pdf/pypdf/security/advisories/GHSA-php9-fj8v-98fj
nvd.nist.gov/vuln/detail/CVE-2026-102998

Code Behaviors & Features

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