CVE-2021-40528
Published: September 6, 2021Last modified: November 8, 2023
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.
Severity score breakdown
| Parameter | Value |
|---|---|
| Base score | 5.9 |
| Attack Vector | NETWORK |
| Attack complexity | HIGH |
| Privileges required | NONE |
| User interaction | NONE |
| Scope | UNCHANGED |
| Confidentiality | HIGH |
| Integrity impact | NONE |
| Availability impact | NONE |
| Vector | CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:N/A:N |
Status
| Product | Release | Package | Status |
|---|---|---|---|
| Alpaquita Linux | 23 LTS | libgcrypt | Not affected (1.10.1-r0) |
| Stream | libgcrypt | Not affected (1.10.2-r2) |
References
- https://eprint.iacr.org/2021/923
- 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-pt1
- https://ibm.github.io/system-security-research-updates/2021/09/06/insecurity-elgamal-pt2
- https://security.gentoo.org/glsa/202210-13