Vulnerability · Published Sep 6, 2021 · Assigned by mitre
CVE-2021-40530
Medium 5.9
In plain English
A medium-severity security flaw in the libcrypto++ package (Debian). There are no confirmed reports of exploitation so far. The chance it is exploited in the next 30 days is estimated at 1.2% (higher than 67% of all known vulnerabilities). Fixed versions are available - upgrade the affected package.
Severity (CVSS NVD)5.9Medium
Exploit odds (30 days)1.2%top 32.8% of all CVEs
Exploited in the wildNo reportsnot in CISA KEV
Attack toolingNoneno public tooling known
Official description
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.
Affected packages & fixed versions
| Ecosystem | Package | Fixed in | Advisory |
|---|---|---|---|
| Debian:12 | libcrypto++ | 8.6.0-1 | DEBIAN-CVE-2021-40530 |
| Debian:13 | libcrypto++ | 8.6.0-1 | DEBIAN-CVE-2021-40530 |
| Debian:14 | libcrypto++ | 8.6.0-1 | DEBIAN-CVE-2021-40530 |
| Ubuntu:22.04:LTS | libcrypto++ | no fix listed | UBUNTU-CVE-2021-40530 |
| Ubuntu:24.04:LTS | libcrypto++ | no fix listed | UBUNTU-CVE-2021-40530 |
| Ubuntu:25.10 | libcrypto++ | no fix listed | UBUNTU-CVE-2021-40530 |
| Ubuntu:26.04:LTS | libcrypto++ | no fix listed | UBUNTU-CVE-2021-40530 |
| Ubuntu:26.10 | libcrypto++ | no fix listed | UBUNTU-CVE-2021-40530 |
Affected products (as reported)
References
- https://eprint.iacr.org/2021/923 x_refsource_MISC
- https://ibm.github.io/system-security-research-updates/2021/07/20/insecurity-elgamal-pt1 x_refsource_MISC
- https://ibm.github.io/system-security-research-updates/2021/09/06/insecurity-elgamal-pt2 x_refsource_MISC
- FEDORA-2021-8b14da0538 vendor-advisory, x_refsource_FEDORA
- FEDORA-2021-a381a721a9 vendor-advisory, x_refsource_FEDORA
- FEDORA-2021-6788250ea4 vendor-advisory, x_refsource_FEDORA