CVE-2021-36978

Severity: medium (CVSS 5.5 v3.1)
Exploited in the wild: not listed in CISA KEV
EPSS: 1.3% probability of exploitation in the next 30 days
Public exploit or detection template: none known
Published: 2021-07-20 · updated 2026-06-17
Weakness: CWE-787

Description

QPDF 9.x through 9.1.1 and 10.x through 10.0.4 has a heap-based buffer overflow in Pl_ASCII85Decoder::write (called from Pl_AES_PDF::flush and Pl_AES_PDF::finish) when a certain downstream write fails.

Affected products

Qpdf Project Qpdf: from 9.0.0 through 9.1.1; from 10.0.0 through 10.0.4

References

https://bugs.chromium.org/p/oss-fuzz/issues/detail?id=28262
https://github.com/google/oss-fuzz-vulns/blob/main/vulns/qpdf/OSV-2020-2245.yaml
https://github.com/qpdf/qpdf/commit/dc92574c10f3e2516ec6445b88c5d584f40df4e5
https://github.com/qpdf/qpdf/issues/492
https://lists.debian.org/debian-lts-announce/2023/08/msg00037.html
https://security.gentoo.org/glsa/202401-20
https://bugs.chromium.org/p/oss-fuzz/issues/detail?id=28262
https://github.com/google/oss-fuzz-vulns/blob/main/vulns/qpdf/OSV-2020-2245.yaml
https://github.com/qpdf/qpdf/commit/dc92574c10f3e2516ec6445b88c5d584f40df4e5
https://github.com/qpdf/qpdf/issues/492
https://lists.debian.org/debian-lts-announce/2023/08/msg00037.html
https://security.gentoo.org/glsa/202401-20

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