Vulnerability · Published Sep 6, 2021 · Assigned by mitre

CVE-2021-40529

Medium 5.9

In plain English

A medium-severity security flaw in the botan package (Alpine). There are no confirmed reports of exploitation so far. The chance it is exploited in the next 30 days is estimated at 1.5% (higher than 75% of all known vulnerabilities). Fixed versions are available - upgrade the affected package.

Severity (CVSS NVD)5.9Medium

Exploit odds (30 days)1.5%top 25.1% of all CVEs

Exploited in the wildNo reportsnot in CISA KEV

Attack toolingNoneno public tooling known

Official 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.

Affected packages & fixed versions

Ecosystem	Package	Fixed in	Advisory
Alpine:v3.20	botan	2.18.1-r3	ALPINE-CVE-2021-40529
Alpine:v3.21	botan	2.18.1-r3	ALPINE-CVE-2021-40529
Debian:12	botan	2.18.1+dfsg-3	DEBIAN-CVE-2021-40529
Debian:13	botan	2.18.1+dfsg-3	DEBIAN-CVE-2021-40529

Affected products (as reported)

Vendor	Product	Versions
n/a	n/a	n/a

References

https://eprint.iacr.org/2021/923 x_refsource_MISC
https://ibm.github.io/system-security-research-updates/2021/07/20/insecurity-elgamal-pt1 x_refsource_MISC
https://ibm.github.io/system-security-research-updates/2021/09/06/insecurity-elgamal-pt2 x_refsource_MISC
https://github.com/randombit/botan/pull/2790 x_refsource_MISC
FEDORA-2021-14b0d97496 vendor-advisory, x_refsource_FEDORA
FEDORA-2021-8d51cac49f vendor-advisory, x_refsource_FEDORA
GLSA-202208-14 vendor-advisory, x_refsource_GENTOO