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.
https://dev.gnupg.org/rCe8b7f10be275bcedb5fc05ed4837a89bfd605c61
https://lists.debian.org/debian-lts-announce/2021/06/msg00021.html
https://www.oracle.com/security-alerts/cpuoct2021.html
https://www.oracle.com/security-alerts/cpujan2022.html
https://www.oracle.com/security-alerts/cpuapr2022.html
Source: MITRE
Published: 2021-06-08
Updated: 2022-12-07
Type: CWE-203
Base Score: 5
Vector: AV:N/AC:L/Au:N/C:P/I:N/A:N
Impact Score: 2.9
Exploitability Score: 10
Severity: MEDIUM
Base Score: 7.5
Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:N
Impact Score: 3.6
Exploitability Score: 3.9
Severity: HIGH