CVE-2021-40529: botan_project botan
Vulnerability summary
CVE-2021-40529 is a medium (CVSS 5.9) vulnerability in botan_project botan. EPSS estimates a 1.53% chance of exploitation in the next 30 days, higher than 74.5% of scored vulnerabilities. 1 public exploit is recorded.
Advisory lineage
Upstream 0 · Downstream 4 · Related 4Timeline
- 06-09-2021PublishedVulnerability first disclosed.
- 04-08-2024Last modifiedVulnerability information updated.
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.
CVSS metrics
5 scores · 4 sources · 2 versions- OSV · AlpineEcosystem advisory · calculated5.9MediumCVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:N/A:N
- OSV · UbuntuEcosystem advisory · calculated5.9MediumCVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:N/A:N
- OSV · DebianEcosystem advisory · calculated5.9MediumCVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:N/A:N
EPSS trend
Probability
1.53%
Chance of exploitation in the next 30 days
Percentile
75%
Versus all other CVEs
30-day change
0.00 pp
From 1.53% on 21-09-2026
Known exploited
Compare KEV catalogsNot in any of the 3 tracked catalogs.
Public exploits
1 foundExploit Reference (ibm.github.io)
Maturity: unknown
Weaknesses
CWE · root causeAffected systems
Ubuntu2 products
- botanAll versions (No fix recorded)
- botan1.10All versions (No fix recorded)
Alpine1 product
- botan< 2.17.3-r3 | < 2.18.1-r3
Botan_project1 product
- botan≤ 2.18.1
Debian1 product
- botan< 2.18.1+dfsg-3
Fedoraproject1 product
- fedoraEOL34 | 35
Mageia1 product
- botan2< 2.17.3-2.1.mga8
Mozilla1 product
- thunderbird< 91.12.0
Opensuse1 product
- Botan&distro=openSUSE Tumbleweed< 2.18.2-1.1
8 vendors · 9 products
References
14 links- ibm.github.io/system-security-research-updates/2021/07/20/insecurity-elgamal-pt1X Refsource MISCREPORTThird Party Advisory
- ibm.github.io/system-security-research-updates/2021/09/06/insecurity-elgamal-pt2X Refsource MISCREPORTExploitThird Party Advisory
