CVEvulnerability
CVE-2021-40529
5.9 MEDIUM
Official page ↗
- Status
- Modified
- Published
- 2021-09-06
- Last modified
- 2026-06-17
- Assigner
- [email protected]
- CVSS 3.1 ([email protected])
- 5.9 MEDIUM — CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:N/A:N
- CVSS 2.0 ([email protected])
- 2.6 LOW — AV:N/AC:H/Au:N/C:P/I:N/A:N
- Weaknesses
- CWE-327
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.
Affected configurations
• botan project botan (<= 2.18.1)
• fedoraproject fedora 34
• fedoraproject fedora 35
• mozilla thunderbird (< 91.12.0)
Related
Weakness · CWE (1)
- CWE-327 Use of a Broken or Risky Cryptographic Algorithm weakness
References
- https://eprint.iacr.org/2021/923 Technical Description, Third Party Advisory
- https://github.com/randombit/botan/pull/2790 Patch, Third Party Advisory
- https://ibm.github.io/system-security-research-updates/2021/07/20/insecurity-elgamal-pt1 Third Party Advisory
- https://ibm.github.io/system-security-research-updates/2021/09/06/insecurity-elgamal-pt2 Exploit, Third Party Advisory
- https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/72NB4OLD3VHJC3YF3PEP2HKF6BYURPAO/ lists.fedoraproject.org
- https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/UPHGYWNJQKWLTUWBNSFB4F66MQDIL3IB/ lists.fedoraproject.org
- https://security.gentoo.org/glsa/202208-14 Third Party Advisory
- https://eprint.iacr.org/2021/923 Technical Description, Third Party Advisory
- https://github.com/randombit/botan/pull/2790 Patch, Third Party Advisory
- https://ibm.github.io/system-security-research-updates/2021/07/20/insecurity-elgamal-pt1 Third Party Advisory
- https://ibm.github.io/system-security-research-updates/2021/09/06/insecurity-elgamal-pt2 Exploit, Third Party Advisory
- https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/72NB4OLD3VHJC3YF3PEP2HKF6BYURPAO/ lists.fedoraproject.org
- https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/UPHGYWNJQKWLTUWBNSFB4F66MQDIL3IB/ lists.fedoraproject.org
- https://security.gentoo.org/glsa/202208-14 Third Party Advisory