An issue was discovered in the _send_secure_msg() function of yubihsm-shell through 2.0.2. The function does not validate the embedded length field of a message received from the device. This could lead to an oversized memcpy() call that will crash the running process. This could be used by an attacker to cause a denial of service.
Conclusion & alert: CVE-2020-24388 is rated High Exploit Risk (72.1/100): CVSS High severity, with medium exploitation likelihood (EPSS 1.73%). Core evidence: 1 public exploit reference(s) are indexed (Exploit-DB). Mandatory action: Public exploits are available—assess exposure, apply mitigations, and prioritize patching.
Risk is dynamic; we continuously reassess and refresh what is shown on this page as upstream context changes.
| EDB-ID | Source | Kind | Published | Link |
|---|---|---|---|---|
| — | nvd_ref | exploit_tag | Exploit-DB ↗ |
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 | 0.79% | 1.73% | +0.95% |
| 2 | 2025-03-30 | 1.63% | 0.79% | -0.84% |
| 3 | 2025-03-29 | — | 1.63% | — |
Full EPSS history (13 records total)
CVSS metrics for this CVE.
| Base score | Version | Severity | Vector | Exploitability | Impact | Score source |
|---|---|---|---|---|---|---|
| 7.5 | 3.1 | HIGH |
|
3.9 | 3.6 | [email protected] |
| 5.0 | 2.0 | MEDIUM |
|
10.0 | 2.9 | [email protected] |
| Vendor | Product | Version | Raw CPE |
|---|---|---|---|
| yubico | yubihsm-shell | <= 2.0.2 | cpe:2.3:a:yubico:yubihsm-shell:*:*:*:*:*:*:*:* |
| fedoraproject | fedora | 33 | cpe:2.3:o:fedoraproject:fedora:33:*:*:*:*:*:*:* |
| URL | Tags |
|---|---|
| https://blog.inhq.net/posts/yubico-libyubihsm-vuln/ | Exploit Third Party Advisory |
| https://developers.yubico.com/yubihsm-shell/ | Vendor Advisory |
| https://github.com/Yubico/yubihsm-shell | Third Party Advisory |
| https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/Y77KQJW76M3PFOBFLBT6DLH2NWHYRNZO/ | |
| https://www.yubico.com/support/security-advisories/ysa-2020-06/ | Vendor Advisory |