Use of a Broken or Risky Cryptographic Algorithm The advisory has been revoked - it doesn't affect any version of package botan (opens in a new tab)
Threat Intelligence
The probability is the direct output of the EPSS model, and conveys an overall sense of the threat of exploitation in the wild. The percentile measures the EPSS probability relative to all known EPSS scores. Note: This data is updated daily, relying on the latest available EPSS model version. Check out the EPSS documentation for more details.
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Test your applications- Snyk IDSNYK-DEBIAN14-BOTAN-11736998
- published10 Aug 2025
- disclosed6 Sept 2021
Introduced: 6 Sep 2021
CVE-2021-40529 (opens in a new tab)Amendment
The Debian security team deemed this advisory irrelevant for Debian:14.
NVD Description
Note: Versions mentioned in the description apply only to the upstream botan package and not the botan package as distributed by Debian.
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.
References
- https://security-tracker.debian.org/tracker/CVE-2021-40529
- https://eprint.iacr.org/2021/923
- https://github.com/randombit/botan/pull/2790
- 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://lists.fedoraproject.org/archives/list/package-announce@lists.fedoraproject.org/message/72NB4OLD3VHJC3YF3PEP2HKF6BYURPAO/
- https://lists.fedoraproject.org/archives/list/package-announce@lists.fedoraproject.org/message/UPHGYWNJQKWLTUWBNSFB4F66MQDIL3IB/
- https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/72NB4OLD3VHJC3YF3PEP2HKF6BYURPAO/
- https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/UPHGYWNJQKWLTUWBNSFB4F66MQDIL3IB/
- https://security.gentoo.org/glsa/202208-14