CVE-2021-33560: Debian Linux

High severity, CVSS 7.5. EPSS: 2.3% chance of exploitation in the next 30 days.

Libgcrypt before 1.8.8 and 1.9.x before 1.9.3 mishandles ElGamal encryption because it lacks exponent blinding to address a side-channel attack against mpi_powm, and the window size is not chosen appropriately. This, for example, affects use of ElGamal in OpenPGP.

Affected products

• Debian Debian Linux: version 9.0 only
• Fedoraproject Fedora: version 33 only; version 34 only
• Gnupg Libgcrypt: before 1.8.8 (fixed in 1.8.8); from 1.9.0, before 1.9.3 (fixed in 1.9.3)
• Oracle Communications Cloud Native Core Binding Support Function: version 1.11.0 only
• Oracle Communications Cloud Native Core Network Function Cloud Native Environment: version 1.9.0 only; version 1.10.0 only
• Oracle Communications Cloud Native Core Network Repository Function: version 1.14.0 only; version 1.15.0 only; version 1.15.1 only
• Oracle Communications Cloud Native Core Network Slice Selection Function: version 1.8.0 only
• Oracle Communications Cloud Native Core Service Communication Proxy: version 1.15.0 only

Published 2021-06-08. Last modified 2026-06-17.