Vulnerability record · CVE-2021-40529 · published 6 September 2021
CVE-2021-40529: Botan project botan broken cryptographic algorithm vulnerability
Botan Project · Botan
The ElGamal implementation in Botan through 2.18.1, as used in Thunderbird and other products, 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.
Description
The ElGamal implementation in Botan through 2.18.1, as used in Thunderbird and other products, 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/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:N/A:N
Affected products
3 vulnerable configurations from NVD's CPE data, grouped by vendor and product.
References
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Related vulnerabilities
Same products first, then exploited flaws of the same weakness class.
Source: NIST National Vulnerability Database (record CVE-2021-40529), CISA KEV, FIRST EPSS (scores of 2026-10-01). This page is refreshed as NVD updates the record.
