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 update: 2024-11-21 Assigner: [email protected] Source: [email protected]
NVD Status：Modified，CVE State: published
View at NVD, CVE.org, EUVD

CVE-2021-24115 is rated High Risk (67.7/100): CVSS Critical severity, with medium exploitation likelihood (EPSS 1.98%). EPSS rose +1.26% over the last day, indicating growing attacker interest. High exploitation likelihood—assess exposure and prioritize remediation.

Risk is dynamic; we continuously reassess and refresh what is shown on this page as upstream context changes.

Exploit prediction scoring system (EPSS) score for CVE-2021-24115

EPSS lead: Daily EPSS estimates relative likelihood of exploitation; percentile ranks this CVE among scored vulnerabilities (higher = more severe relative rank).

# Date Old EPSS score New EPSS score Delta (New - Old)
1 2026-06-15 0.71% 1.98% +1.26%
2 2025-03-30 2.23% 0.71% -1.52%
3 2025-03-29 — 2.23% —

Full EPSS history (10 records total)

Common vulnerability scoring system (CVSS) metrics for CVE-2021-24115

CVSS metrics for this CVE.

Base score Version Severity Vector Exploitability Impact Score source
9.8 3.1 CRITICAL
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H Click to expand
Attack vector (AV:N)
Could be attacked over the internet or any normal routed network—not just someone sitting at the machine.
Attack complexity (AC:L)
Once they can reach the bug, pulling it off is straightforward—no weird race conditions or rare setup.
Privileges required (PR:N)
No account or special rights needed—anonymous or random user is enough.
User interaction (UI:N)
Nobody has to click “OK” or open a trap file; it can work without a victim helping.
Scope (S:U)
Damage stays in the same “trust bubble” as the broken component—no big spill into unrelated systems.
Confidentiality (C:H)
Serious risk that confidential data gets exposed in a big way.
Integrity (I:H)
They could widely tamper with or forge data—trust in the data is badly hurt.
Availability (A:H)
Could take the service down hard or make it unusable for people who depend on it.
 3.9 5.9 [email protected]
7.5 2.0 HIGH
AV:N/AC:L/Au:N/C:P/I:P/A:P Click to expand
Access vector (AV:N)
Can be exploited remotely over network reachability.
Access complexity (AC:L)
Exploitation conditions are straightforward and predictable.
Authentication (AU:N)
No authentication is required.
Confidentiality impact (C:P)
Partial confidentiality impact.
Integrity impact (I:P)
Partial integrity impact.
Availability impact (A:P)
Partial availability impact.
 10.0 6.4 [email protected]

Weakness enumeration for CVE-2021-24115

OS Trackers for CVE-2021-24115

vendor priority summary link
alpine critical CVE-2021-24115: 1 source package rows (botan); 24 state rows across 8 repos (3.11-main, 3.12-main, 3.17-main, 3.18-main, 3.19-main, 3.20-main, 3.21-main, edge-main); fixed 8, open 16. https://security.alpinelinux.org/vuln/CVE-2021-24115
debian not yet assigned CVE-2021-24115 not yet assigned priority: Debian including 1 source packages (botan), 3 status rows across 3 suites (bookworm, bullseye, trixie): resolved 3. https://security-tracker.debian.org/tracker/CVE-2021-24115
suse critical CVE-2021-24115 severity critical: SUSE including 21 source package names (Botan-2.10.0-bp151.3.3.1, Botan-2.10.0-bp152.4.6.1, …), 25 product×package rows across 3 product lines (SUSE Package Hub 15 SP1, SUSE Package Hub 15 SP2, openSUSE Leap 15.2): Fixed 25. https://www.suse.com/security/cve/CVE-2021-24115/
ubuntu low CVE-2021-24115 low priority: Ubuntu including 2 source packages (botan, botan1.10), 32 status rows across 16 suites (bionic, focal, groovy, hirsute, impish, jammy, kinetic, lunar, mantic, noble, oracular, plucky, questing, trusty, upstream, xenial): DNE 14, not-affected 10, needs-triage 6, ignored 1, released 1. https://ubuntu.com/security/CVE-2021-24115

Affected software / configurations for CVE-2021-24115

Vendor Product Version Raw CPE
botan_project botan < 2.17.3 cpe:2.3:a:botan_project:botan:*:*:*:*:*:*:*:*

References for CVE-2021-24115

URL Tags
https://botan.randombit.net/news.html Release Notes Vendor Advisory
https://github.com/randombit/botan/compare/2.17.2...2.17.3 Patch Third Party Advisory
https://github.com/randombit/botan/pull/2549 Patch Third Party Advisory
cvelogic Threat Intelligence