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5.9
CVE-2021-40530: The 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...
CVE-2021-40530 · published 5 years ago
Summary
The 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 epheme...
What to do
- Update debian libcrypto++ to version 8.6.0-1.
Affected software
| Ecosystem | Vendor | Product | Affected versions |
|---|---|---|---|
| – | cryptopp | crypto\+\+ |
<= 8.5 cpe:2.3:a:cryptopp:crypto\+\+:*:*:*:*:*:*:*:* |
| – | fedoraproject | fedora |
33 34 35 cpe:2.3:o:fedoraproject:fedora:33:*:*:*:*:*:*:* |
| Ubuntu:Pro:14.04:LTS | canonical | libcrypto++ | All versions |
| Debian:12 | debian | libcrypto++ |
< 8.6.0-1 Fix: upgrade to 8.6.0-1
|
Original advisory text
The 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 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.
References
- https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedorapro... URL
- https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedorapro... URL
- https://ubuntu.com/security/CVE-2021-40530 Third Party Advisory
- https://github.com/weidai11/cryptopp/issues/1059 Third Party Advisory
- https://eprint.iacr.org/2021/923 Third Party Advisory
- https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedorapro... URL
- https://ibm.github.io/system-security-research-updates/2021/07/20/insecurity-elg... Third Party Advisory
- https://ibm.github.io/system-security-research-updates/2021/09/06/insecurity-elg... Third Party Advisory
- https://www.cve.org/CVERecord?id=CVE-2021-40530 Third Party Advisory
- https://security-tracker.debian.org/tracker/CVE-2021-40530 Vendor Advisory
Internet-facing
14 days
Internal
60 days
- Not known to be exploited
- Can be exploited automatically (estimated)
- Gives an attacker partial control (estimated)
Type
CWE-327Use of a Broken Cryptographic Algorithm
Timeline
Published6 Sep 2021
Updated4 Nov 2026
First seen29 Sep 2026
Sources
CVE-2021-40530 · NVD
UBUNTU-CVE-2021-40530 · OSV
CVE-2021-40530 · OSV
DEBIAN-CVE-2021-40530 · OSV
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