CVE-2021-40528

critical

Description

The ElGamal implementation in Libgcrypt before 1.9.4 allows plaintext recovery because, during interaction between two cryptographic libraries, a certain dangerous combination of the prime defined by the receiver's public key, the generator defined by the receiver's public key, and the sender's ephemeral exponents can lead to a cross-configuration attack against OpenPGP.

References

Advisories
More

https://security.gentoo.org/glsa/202210-13

https://ibm.github.io/system-security-research-updates/2021/07/20/insecurity-elgamal-pt1

https://eprint.iacr.org/2021/923

https://ibm.github.io/system-security-research-updates/2021/09/06/insecurity-elgamal-pt2

https://git.gnupg.org/cgi-bin/gitweb.cgi?p=libgcrypt.git%3Ba=commit%3Bh=3462280f2e23e16adf3ed5176e0f2413d8861320

Details

Source: Mitre, NVD

Published: 2021-09-06

Updated: 2024-11-21

Risk Information

CVSS v2

Base Score: 2.6

Vector: CVSS2#AV:N/AC:H/Au:N/C:P/I:N/A:N

Severity: Low

CVSS v3

Base Score: 5.9

Vector: CVSS:3.0/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:N/A:N

Severity: Medium

CVSS v4

Base Score: 9.3

Vector: CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N

Severity: Critical

EPSS

EPSS: 0.00069