Vulnerability Details : CVE-2021-40529
Potential exploit
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.
Products affected by CVE-2021-40529
- cpe:2.3:a:mozilla:thunderbird:*:*:*:*:*:*:*:*
- cpe:2.3:o:fedoraproject:fedora:34:*:*:*:*:*:*:*
- cpe:2.3:o:fedoraproject:fedora:35:*:*:*:*:*:*:*
- cpe:2.3:a:botan_project:botan:*:*:*:*:*:*:*:*
Exploit prediction scoring system (EPSS) score for CVE-2021-40529
0.29%
Probability of exploitation activity in the next 30 days
EPSS Score History
~ 69 %
Percentile, the proportion of vulnerabilities that are scored at or less
CVSS scores for CVE-2021-40529
Base Score | Base Severity | CVSS Vector | Exploitability Score | Impact Score | Score Source | First Seen |
---|---|---|---|---|---|---|
2.6
|
LOW | AV:N/AC:H/Au:N/C:P/I:N/A:N |
4.9
|
2.9
|
NIST | |
5.9
|
MEDIUM | CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:N/A:N |
2.2
|
3.6
|
NIST |
CWE ids for CVE-2021-40529
-
The product uses a broken or risky cryptographic algorithm or protocol.Assigned by: nvd@nist.gov (Primary)
References for CVE-2021-40529
-
https://ibm.github.io/system-security-research-updates/2021/09/06/insecurity-elgamal-pt2
On the (in)security of ElGamal in OpenPGP - Part II - Syssec@IBM ResearchExploit;Third Party Advisory
-
https://eprint.iacr.org/2021/923
Cryptology ePrint Archive: Report 2021/923 - On the (in)security of ElGamal in OpenPGPTechnical Description;Third Party Advisory
-
https://ibm.github.io/system-security-research-updates/2021/07/20/insecurity-elgamal-pt1
On the (in)security of ElGamal in OpenPGP - Part I - Syssec@IBM ResearchThird Party Advisory
-
https://lists.fedoraproject.org/archives/list/package-announce@lists.fedoraproject.org/message/72NB4OLD3VHJC3YF3PEP2HKF6BYURPAO/
[SECURITY] Fedora 34 Update: botan2-2.17.3-4.fc34 - package-announce - Fedora Mailing-ListsMailing List;Third Party Advisory
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https://lists.fedoraproject.org/archives/list/package-announce@lists.fedoraproject.org/message/UPHGYWNJQKWLTUWBNSFB4F66MQDIL3IB/
[SECURITY] Fedora 35 Update: botan2-2.18.2-1.fc35 - package-announce - Fedora Mailing-ListsMailing List;Third Party Advisory
-
https://security.gentoo.org/glsa/202208-14
Mozilla Thunderbird: Multiple Vulnerabilities (GLSA 202208-14) — Gentoo securityThird Party Advisory
-
https://github.com/randombit/botan/pull/2790
Avoid using short exponents with ElGamal by randombit · Pull Request #2790 · randombit/botan · GitHubPatch;Third Party Advisory
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