CVE-2021-40529 Information

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 Vector

CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:N/A:N

Reference

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://github.com/randombit/botan/pull/2790 https://eprint.iacr.org/2021/923 https://lists.fedoraproject.org/archives/list/package-announce@lists.fedoraproject.org/message/UPHGYWNJQKWLTUWBNSFB4F66MQDIL3IB/ https://lists.fedoraproject.org/archives/list/package-announce@lists.fedoraproject.org/message/72NB4OLD3VHJC3YF3PEP2HKF6BYURPAO/

Attack Complexity

HIGH

Privileges Required

NONE

User Interaction Required

NONE

Scope

NONE

Confidentiality Impact

UNCHANGED

Integrity Impact

HIGH

Availability Impact

NONE

Base Score

NONE

Base Severity

5.9