CVE-2021-40528 Information

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.

CVSS Vector

CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:N/A:N

Reference

https://ibm.github.io/system-security-research-updates/2021/07/20/insecurity-elgamal-pt1 https://ibm.github.io/system-security-research-updates/2021/09/06/insecurity-elgamal-pt2 https://eprint.iacr.org/2021/923 https://git.gnupg.org/cgi-bin/gitweb.cgi?p=libgcrypt.git;a=commit;h=3462280f2e23e16adf3ed5176e0f2413d8861320

Attack Complexity

HIGH

Privileges Required

NONE

User Interaction Required

NONE

Scope

NONE

Confidentiality Impact

UNCHANGED

Integrity Impact

HIGH

Availability Impact

NONE

Base Score

NONE

Base Severity

5.9