CVE-2021-40530
MEDIUMCrypto++ < 8.5 - Plaintext Recovery via ElGamal Cross-Configuration Attack
Title source: llmDescription
The ElGamal implementation in Crypto++ through 8.5 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 (6)
Core 6
Core References
Technical Description, Third Party Advisory x_refsource_misc
https://eprint.iacr.org/2021/923
Third Party Advisory x_refsource_misc
https://ibm.github.io/system-security-research-updates/2021/07/20/insecurity-elgamal-pt1
Exploit, Third Party Advisory x_refsource_misc
https://ibm.github.io/system-security-research-updates/2021/09/06/insecurity-elgamal-pt2
Mailing List, Third Party Advisory vendor-advisory
x_refsource_fedora
https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/HGVBZ2TTRKCTYAZTRHTF6OBD4W37F5MT/
Mailing List, Third Party Advisory vendor-advisory
x_refsource_fedora
https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/57OJA2K5AHX5HAU2QBDRWLGIIUX7GASC/
Mailing List, Third Party Advisory vendor-advisory
x_refsource_fedora
https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/VJYOZGWI7TD27SEXILSM6VUTPPEICDL7/
Scores
CVSS v3
5.9
EPSS
0.0026
EPSS Percentile
49.1%
Attack Vector
NETWORK
CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:N/A:N
Details
CWE
CWE-327
Status
published
Products (4)
cryptopp/crypto\+\+
< 8.5
fedoraproject/fedora
33
fedoraproject/fedora
34
fedoraproject/fedora
35
Published
Sep 06, 2021
Tracked Since
Feb 18, 2026