Vulnerability in Gnupg Libgcrypt
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 the receiver's public key, and the sender's ephemeral exponents can lead to a cross-configuration attack against OpenPGP.
Vulnerability class: POODLE (CVE-2014-3566)
Published · last modified .
CVSS v3 metric
CVSS v3 base score 5.9 (Medium). Vector: CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:N/A:N.
EPSS exploit prediction
EPSS: 0.014 (72.6th percentile), scored .
Low probability of exploitation in the next 30 days, but still tracked. 73rd percentile — 72.6% of CVEs in the catalogue have a lower EPSS than this one. How to read EPSS.
EPSS over last 30 days · oldest: 0.014 · newest: 0.014 · change: 0.000
Affected products
Weakness classification (CWE)
Public proof-of-concept exploits
References
- eprint.iacr.org/2021/923 (Technical Description, Third Party Advisory)
- ibm.github.io/system-security-research-updates/2021/07/20/insecurity-elgamal-pt1 (Third Party Advisory)
- ibm.github.io/system-security-research-updates/2021/09/06/insecurity-elgamal-pt2 (Exploit, Third Party Advisory)
- git.gnupg.org/cgi-bin/gitweb.cgi
- security.gentoo.org/glsa/202210-13 (vendor-advisory, Third Party Advisory)
Frequently asked questions
- What is CVE-2021-40528?
- CVE-2021-40528 is a medium-severity vulnerability in Gnupg Libgcrypt, classified under Use of a Broken or Risky Cryptographic Algorithm. CVSS score: 5.9/10. Published 2021-09-06.
- How severe is CVE-2021-40528?
- Medium severity. CVSS v3 base score is 5.9 out of 10.
- Is CVE-2021-40528 known to be exploited?
- 3 public proof-of-concept repositories are indexed. Not currently listed in the CISA KEV catalog.