CVE-2021-40530

NameCVE-2021-40530
DescriptionThe ElGamal implementation in Crypto++ through 8.5 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.
SourceCVE (at NVD; CERT, LWN, oss-sec, fulldisc, Red Hat, Ubuntu, Gentoo, SUSE bugzilla/CVE, GitHub advisories/code/issues, web search, more)
Debian Bugs993841

Vulnerable and fixed packages

The table below lists information on source packages.

Source PackageReleaseVersionStatus
libcrypto++ (PTS)jessie, jessie (lts)5.6.1-6+deb8u3vulnerable
stretch5.6.4-7vulnerable
buster5.6.4-8vulnerable
bullseye8.4.0-1vulnerable
bookworm8.7.0+git220824-1fixed
sid, trixie8.9.0-1.1fixed

The information below is based on the following data on fixed versions.

PackageTypeReleaseFixed VersionUrgencyOriginDebian Bugs
libcrypto++sourcejessie(unfixed)end-of-life
libcrypto++source(unstable)8.6.0-1993841

Notes

[bullseye] - libcrypto++ <no-dsa> (Minor issue)
[buster] - libcrypto++ <no-dsa> (Minor issue)
[stretch] - libcrypto++ <no-dsa> (Minor issue)
https://eprint.iacr.org/2021/923
https://github.com/weidai11/cryptopp/issues/1059
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/weidai11/cryptopp/commit/bee8e8ca6658 (CRYPTOPP_8_6_0)

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