CVE-2021-3405: Debian Linux

Medium severity, CVSS 6.5. EPSS: 1.7% chance of exploitation in the next 30 days.

A flaw was found in libebml before 1.4.2. A heap overflow bug exists in the implementation of EbmlString::ReadData and EbmlUnicodeString::ReadData in libebml.

Affected products

• Debian Debian Linux: version 9.0 only
• Fedoraproject Fedora: version 32 only; version 33 only; version 34 only
• Matroska Libebml: before 1.4.2 (fixed in 1.4.2)

Published 2021-02-23. Last modified 2026-06-17.