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 the prime defined by the receiver's public key, the generator defined by…
Does this matter?
Lower severity and a low EPSS score (1.42%). Track it; it rarely justifies an emergency change on its own.
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 3.1
- 5.9 MEDIUMCVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:N/A:N
- EPSS
- 1.42% probability · 71th percentile
- CISA KEV
- Not listed
- Weakness
- CWE-327
- Affected
- gnupg/libgcrypt
- Source
- cve@mitre.org
References
- https://eprint.iacr.org/2021/923Technical Description, Third Party Advisory
- https://git.gnupg.org/cgi-bin/gitweb.cgi?p=libgcrypt.git%3Ba=commit%3Bh=3462280f2e23e16adf3ed5176e0f2413d8861320
- https://ibm.github.io/system-security-research-updates/2021/07/20/insecurity-elgamal-pt1Third Party Advisory
- https://ibm.github.io/system-security-research-updates/2021/09/06/insecurity-elgamal-pt2Exploit, Third Party Advisory
- https://security.gentoo.org/glsa/202210-13Third Party Advisory
- https://eprint.iacr.org/2021/923Technical Description, Third Party Advisory
- https://git.gnupg.org/cgi-bin/gitweb.cgi?p=libgcrypt.git%3Ba=commit%3Bh=3462280f2e23e16adf3ed5176e0f2413d8861320
- https://ibm.github.io/system-security-research-updates/2021/07/20/insecurity-elgamal-pt1Third Party Advisory
- https://ibm.github.io/system-security-research-updates/2021/09/06/insecurity-elgamal-pt2Exploit, Third Party Advisory
- https://security.gentoo.org/glsa/202210-13Third Party Advisory
Source: NVD record, EPSS from FIRST.org, KEV from CISA. Refreshed daily.