Medium severity · published Sep 6, 2021
CVE-2021-40528
The ElGamal implementation in Libgcrypt before 1.9.4 allows plaintext recovery because, during interaction between two cryptographic libraries, a certain dangerous combination of…
5.9
CVSS
1.4%
EPSS
No
On KEV
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
Attack vector
Network
Complexity
High
Privileges
None
User interaction
None
Confidentiality
High
Integrity
None
Availability
None
Scope
Unchanged
Exploitation
Is it being used?
Exploit prediction (EPSS)1.4% · higher than 73% of CVEs
Exploited in the wildNo evidence yet
CISA KEVNot listed
Ransomware campaign useNot known
Affected products
Which versions
LI
Libgcrypt · Gnupg
before 1.9.4 · source: NVD
References
NVD
https://nvd.nist.gov/vuln/detail/CVE-2021-40528
CVE.org
https://www.cve.org/CVERecord?id=CVE-2021-40528
Technical Description
https://eprint.iacr.org/2021/923
git.gnupg.org
https://git.gnupg.org/cgi-bin/gitweb.cgi?p=libgcrypt.git%3Ba=commit%3Bh=3462280f2e23e16adf3ed5176e0f2413d8861320
Third Party Advisory
https://ibm.github.io/system-security-research-updates/2021/07/20/insecurity-elgamal-pt1
Exploit
https://ibm.github.io/system-security-research-updates/2021/09/06/insecurity-elgamal-pt2
Third Party Advisory
https://security.gentoo.org/glsa/202210-13
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