CVE-2021-40528
libgcrypt: ElGamal implementation allows plaintext recovery
Severity
ModerateRed Hat Product Security
CVSS 3.1
Review impact separately from score.
Published · July 20, 2021
Updated · November 21, 2025
Description
A flaw was found in libgcrypt's ElGamal implementation, where it allows plain text recovery. During the interaction between two cryptographic libraries, a certain 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. The highest threat from this vulnerability is to confidentiality.
Statement
Please note that there was a mixup between this CVE and CVE-2021-33560. At this time, both CVEs should be assumed to refer to the same issue. More information will be provided in the near future. See the first link in External References for more information.
CVSS score applicability
The CVSS score(s) listed for this vulnerability do not reflect the associated product's status, and are included for informational purposes to better understand the severity of this vulnerability.
Mitigation
No mitigation is specified in collected source.
CVSS / CWE
CVSS 3.1 · 5.9CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:N/A:N
CWE not specified