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Bug 811906 - dev-libs/botan: ElGamal plaintext recovery (CVE-2021-40529)
Summary: dev-libs/botan: ElGamal plaintext recovery (CVE-2021-40529)
Alias: None
Product: Gentoo Security
Classification: Unclassified
Component: Vulnerabilities (show other bugs)
Hardware: All Linux
: Normal minor (vote)
Assignee: Gentoo Security
Whiteboard: B4 [upstream/ebuild]
Depends on:
Blocks: CVE-2021-40529
  Show dependency tree
Reported: 2021-09-07 01:31 UTC by John Helmert III
Modified: 2021-09-07 01:38 UTC (History)
1 user (show)

See Also:
Package list:
Runtime testing required: ---


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Description John Helmert III gentoo-dev Security 2021-09-07 01:31:09 UTC
CVE-2021-40529 (,

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: