Bug 811906

Summary:	<dev-libs/botan-2.18.2: ElGamal plaintext recovery (CVE-2021-40529)
Product:	Gentoo Security	Reporter:	John Helmert III <ajak>
Component:	Vulnerabilities	Assignee:	Gentoo Security <security>
Status:	IN_PROGRESS ---
Severity:	minor	CC:	sam
Priority:	Normal
Version:	unspecified
Hardware:	All
OS:	Linux
Whiteboard:	B4 [glsa?]
Package list:		Runtime testing required:	---
Bug Depends on:	824922
Bug Blocks:	811909

Description John Helmert III archtester

2021-09-07 01:31:09 UTC

CVE-2021-40529 (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):

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.

Unreleased patch: https://github.com/randombit/botan/pull/2790

Comment 1 Sam James archtester

2021-11-19 12:54:05 UTC

I'm sorry, this was fixed in 2.18.2.

Comment 2 John Helmert III archtester

2021-11-20 17:16:58 UTC

Please cleanup.

Comment 3 Sam James archtester

2022-01-01 09:39:48 UTC

sorry, forgot about this bug: https://github.com/gentoo/gentoo/commit/b4c6d315ef4456f223851a4aeee6892d26571a32