{"cve":"CVE-2021-40529","nvd":{"published":"2021-09-06T19:15:07.630","modified":"2026-06-17T04:07:05.827","status":"Modified","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_v4":null,"cvss_v3":{"version":"3.1","vector":"CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:N/A:N","score":5.9},"cwes":["CWE-327"],"references":["https://eprint.iacr.org/2021/923","https://github.com/randombit/botan/pull/2790","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://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/72NB4OLD3VHJC3YF3PEP2HKF6BYURPAO/"],"products":["botan_project:botan","fedoraproject:fedora","mozilla:thunderbird"],"source":"nvd","synced_at":"2026-10-19T21:21:57.125947417+00:00"},"epss":{"cve":"CVE-2021-40529","score":0.01532,"percentile":0.74782,"date":"2026-10-31"},"kev":null,"osv":[],"attribution":["This product uses the NVD API but is not endorsed or certified by the NVD.","EPSS scores: FIRST Exploit Prediction Scoring System, https://www.first.org/epss","Known exploited vulnerabilities: CISA Known Exploited Vulnerabilities Catalog, https://www.cisa.gov/known-exploited-vulnerabilities-catalog","Package advisories: OSV (https://osv.dev), from the GitHub Advisory Database, PyPA, Go, RustSec and other ecosystem databases, under CC-BY 4.0 or CC0","CVE records: the CVE Program's CVE List (https://www.cve.org), under its terms of use (https://www.cve.org/Legal/TermsOfUse). CVE is a registered trademark of The MITRE Corporation; this product is not affiliated with the CVE Program."]}