What is CVE-2021-24115?

CVE-2021-24115 is a critical-severity vulnerability in Botan Project. CVSS score: 9.8/10. Published 2021-02-22.

How severe is CVE-2021-24115?

Critical severity. CVSS v3 base score is 9.8 out of 10.

Vulnerability in Botan Project

CVE-2021-24115

In Botan before 2.17.3, constant-time computations are not used for certain decoding and encoding operations (base32, base58, base64, and hex).

Published 2021-02-22 · last modified 2026-06-17.

CVSS v3 metric

CVSS v3 base score 9.8 (Critical). Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H.

EPSS exploit prediction

EPSS: 0.019 (79.6th percentile), scored 2026-10-20.

Low probability of exploitation in the next 30 days, but still tracked. 80th percentile — 79.6% of CVEs in the catalogue have a lower EPSS than this one. How to read EPSS.

EPSS over last 30 days · oldest: 0.020 · newest: 0.019 · change: -0.001

Affected products

Botan Project

References

github.com/randombit/botan/compare/2.17.2...2.17.3 (Patch, Third Party Advisory)
github.com/randombit/botan/pull/2549 (Patch, Third Party Advisory)
botan.randombit.net/news.html (Release Notes, Vendor Advisory)

Frequently asked questions

What is CVE-2021-24115?: CVE-2021-24115 is a critical-severity vulnerability in Botan Project. CVSS score: 9.8/10. Published 2021-02-22.
How severe is CVE-2021-24115?: Critical severity. CVSS v3 base score is 9.8 out of 10.