CVE-2021-40529
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…
Does this matter?
Lower severity and a low EPSS score (1.53%). Track it; it rarely justifies an emergency change on its own.
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 3.1
- 5.9 MEDIUMCVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:N/A:N
- EPSS
- 1.53% probability · 73th percentile
- CISA KEV
- Not listed
- Weakness
- CWE-327
- Affected
- botan project/botan · fedoraproject/fedora · mozilla/thunderbird
- Source
- cve@mitre.org
References
- https://eprint.iacr.org/2021/923Technical Description, Third Party Advisory
- https://github.com/randombit/botan/pull/2790Patch, Third Party Advisory
- https://ibm.github.io/system-security-research-updates/2021/07/20/insecurity-elgamal-pt1Third Party Advisory
- https://ibm.github.io/system-security-research-updates/2021/09/06/insecurity-elgamal-pt2Exploit, Third Party Advisory
- https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/72NB4OLD3VHJC3YF3PEP2HKF6BYURPAO/
- https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/UPHGYWNJQKWLTUWBNSFB4F66MQDIL3IB/
- https://security.gentoo.org/glsa/202208-14Third Party Advisory
- https://eprint.iacr.org/2021/923Technical Description, Third Party Advisory
- https://github.com/randombit/botan/pull/2790Patch, Third Party Advisory
- https://ibm.github.io/system-security-research-updates/2021/07/20/insecurity-elgamal-pt1Third Party Advisory
- https://ibm.github.io/system-security-research-updates/2021/09/06/insecurity-elgamal-pt2Exploit, Third Party Advisory
- https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/72NB4OLD3VHJC3YF3PEP2HKF6BYURPAO/
- https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/UPHGYWNJQKWLTUWBNSFB4F66MQDIL3IB/
- https://security.gentoo.org/glsa/202208-14Third Party Advisory
Source: NVD record, EPSS from FIRST.org, KEV from CISA. Refreshed daily.