CVE-2021-40528
First published: Mon Sep 06 2021(Updated: )
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.
Credit: cve@mitre.org
| Affected Software | Affected Version | How to fix |
|---|---|---|
| GNU Libgcrypt | <1.9.4 |
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Reference Links
- https://eprint.iacr.org/2021/923
- https://git.gnupg.org/cgi-bin/gitweb.cgi?p=libgcrypt.git;a=commit;h=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
- https://git.gnupg.org/cgi-bin/gitweb.cgi?p=libgcrypt.git%3Ba=commit%3Bh=3462280f2e23e16adf3ed5176e0f2413d8861320
Frequently Asked Questions
What is the vulnerability ID for this vulnerability?
The vulnerability ID for this vulnerability is CVE-2021-40528.
What is the severity of CVE-2021-40528?
The severity of CVE-2021-40528 is medium with a CVSS score of 5.9.
Which software is affected by CVE-2021-40528?
The software affected by CVE-2021-40528 is GnuPG Libgcrypt version up to 1.9.4.
How can the plaintext recovery vulnerability be exploited?
The plaintext recovery vulnerability can be exploited during interaction between two cryptographic libraries by using a certain dangerous combination of the prime, generator, and ephemeral public key.
Is there a fix available for CVE-2021-40528?
Yes, the fix for CVE-2021-40528 is available in Libgcrypt version 1.9.4.
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