Description
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.
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 13 | botan | 2.18.1+dfsg-3 | — |
| Debian 12 | botan | 2.18.1+dfsg-3 | — |
Ubuntu
Security tracker ↗| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| Ubuntu 20.04 LTS | botan | No fix yet | — |
| Ubuntu 18.04 LTS | botan +1 | No fix yet | — |
| Ubuntu 16.04 LTS | botan1.10 | No fix yet | — |
Show 2 more (older releases, extended support, other products)Fewer releases
| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| Ubuntu Pro 22.04 LTS | botan | No fix yet | — |
| Ubuntu Pro 14.04 LTS | botan1.10 | No fix yet | — |
SUSE
Security tracker ↗| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| SLES 15 SP3 | MozillaThunderbird | 91.4.0-8.45.2 | SUSE-SU-2021:4150-1 |
| SLES 15 SP2 | MozillaThunderbird | 91.4.0-8.45.2 | SUSE-SU-2021:4150-1 |
openSUSE
Security tracker ↗| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| openSUSE Tumbleweed | Botan | 2.18.2-1.1 | openSUSE-SU-2024:11661-1 |
| openSUSE Tumbleweed | MozillaThunderbird | 91.4.0-1.1 | openSUSE-SU-2024:11670-1 |
| openSUSE Leap 15.3 | MozillaThunderbird | 91.4.0-8.45.2 | openSUSE-SU-2021:4150-1 |
| openSUSE Leap 15.2 | MozillaThunderbird | 91.4.0-lp152.2.52.1 | openSUSE-SU-2021:1635-1 |
Alpine
Security tracker ↗| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| Alpine v3.21 | botan | 2.18.1-r3 | — |
| Alpine v3.20 | botan | 2.18.1-r3 | — |
| Alpine v3.19 | botan | 2.18.1-r3 | — |
| Alpine v3.18 | botan | 2.18.1-r3 | — |
| Alpine v3.17 | botan | 2.18.1-r3 | — |
Show 3 more (older releases, extended support, other products)Fewer releases
| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| Alpine v3.16 | botan | 2.18.1-r3 | — |
| Alpine v3.15 | botan | 2.18.1-r3 | — |
| Alpine v3.14 | botan | 2.17.3-r3 | — |
Advisories 5
- openSUSE-SU-2024:11661-1 Botan-2.18.2-1.1 on GA media SUSE / openSUSE Security Updates · Feb 4, 2026
- SUSE-SU-2021:4150-1 Security update for MozillaThunderbird SUSE / openSUSE Security Updates · Feb 4, 2026
- openSUSE-SU-2021:4150-1 Security update for MozillaThunderbird SUSE / openSUSE Security Updates · Feb 4, 2026
- openSUSE-SU-2021:1635-1 Security update for MozillaThunderbird SUSE / openSUSE Security Updates · Feb 4, 2026
- openSUSE-SU-2024:11670-1 MozillaThunderbird-91.4.0-1.1 on GA media SUSE / openSUSE Security Updates · May 7, 2025
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
- https://github.com/randombit/botan/pull/2790
- FEDORA-2021-14b0d97496 vendor-advisory
- FEDORA-2021-8d51cac49f vendor-advisory
- GLSA-202208-14 vendor-advisory