Description
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.
Fixed in Linux distributions
Distributions backport fixes, so the version that fixes this vulnerability differs per release — upgrade to at least the version shown. From the distributions' security trackers and advisories.
Debian
Security tracker ↗| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| Debian 14 | libcrypto++ | 8.6.0-1 | — |
| Debian 13 | libcrypto++ | 8.6.0-1 | — |
| Debian 12 | libcrypto++ | 8.6.0-1 | — |
Ubuntu
Security tracker ↗| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| Ubuntu 26.10 | libcrypto++ | No fix yet | — |
| Ubuntu 26.04 LTS | libcrypto++ | No fix yet | — |
| Ubuntu 25.10 | libcrypto++ | No fix yet | — |
| Ubuntu 24.04 LTS | libcrypto++ | No fix yet | — |
| Ubuntu 22.04 LTS | libcrypto++ | No fix yet | — |
Show 4 more (older releases, extended support, other products)Fewer releases
| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| Ubuntu 20.04 LTS | libcrypto++ | No fix yet | — |
| Ubuntu 18.04 LTS | libcrypto++ | No fix yet | — |
| Ubuntu Pro 16.04 LTS | libcrypto++ | No fix yet | — |
| Ubuntu Pro 14.04 LTS | libcrypto++ | No fix yet | — |
openSUSE
Security tracker ↗| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| openSUSE Tumbleweed | libcryptopp | 8.6.0-1.1 | openSUSE-SU-2024:10933-1 |
Advisories 1
- openSUSE-SU-2024:10933-1 libcryptopp-devel-8.6.0-1.1 on GA media SUSE / openSUSE Security Updates · Feb 4, 2026
References
- https://eprint.iacr.org/2021/923
- 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
- FEDORA-2021-8b14da0538 vendor-advisory
- FEDORA-2021-a381a721a9 vendor-advisory
- FEDORA-2021-6788250ea4 vendor-advisory