How severe is CVE-2020-24388?

CVE-2020-24388 has a CVSS 3.x base score of 7.5, rated high severity. It is exploitable over network with low attack complexity, requires no privileges and no user interaction. Impact on confidentiality is none, integrity none, and availability high.

Is CVE-2020-24388 being actively exploited?

It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 2% (75th percentile), an estimate of the probability of exploitation in the next 30 days.

What products are affected by CVE-2020-24388?

CVE-2020-24388 primarily affects Yubico Yubihsm-shell. In total, 2 product configurations (CPEs) are listed as vulnerable; see the affected-products list for the exact versions.

How do I fix CVE-2020-24388?

Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround. Given its high severity, prioritise patching exposed systems.

When was CVE-2020-24388 published?

CVE-2020-24388 was published on 2020-10-19 and last updated on 2026-06-17.

CVE-2020-24388

CVE-2020-24388 is a high-severity vulnerability in Yubico Yubihsm-shell with a CVSS 3.x base score of 7.5. It is not currently listed as actively exploited by CISA, and its EPSS exploit-prediction score is low. The underlying weakness is classified as CWE-20.

Key facts

Severity: High (CVSS 3.x base score 7.5)
CVSS v2: 5.0
EPSS exploit prediction: 2% (75th percentile)
Actively exploited: Not listed in CISA KEV
Weakness: CWE-20
Affected product: Yubico Yubihsm-shell
Published: 2020-10-19
Last modified: 2026-06-17

Description

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.

Frequently asked questions

What is CVE-2020-24388?: 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.
How severe is CVE-2020-24388?: CVE-2020-24388 has a CVSS 3.x base score of 7.5, rated high severity. It is exploitable over network with low attack complexity, requires no privileges and no user interaction. Impact on confidentiality is none, integrity none, and availability high.
Is CVE-2020-24388 being actively exploited?: It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 2% (75th percentile), an estimate of the probability of exploitation in the next 30 days.
What products are affected by CVE-2020-24388?: CVE-2020-24388 primarily affects Yubico Yubihsm-shell. In total, 2 product configurations (CPEs) are listed as vulnerable; see the affected-products list for the exact versions.
How do I fix CVE-2020-24388?: Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround. Given its high severity, prioritise patching exposed systems.
When was CVE-2020-24388 published?: CVE-2020-24388 was published on 2020-10-19 and last updated on 2026-06-17.

References

Affected products (2)

cpe:2.3:a:yubico:yubihsm-shell:*:*:*:*:*:*:*:*
cpe:2.3:o:fedoraproject:fedora:33:*:*:*:*:*:*:*

More vulnerabilities in Yubico Yubihsm-shell

CVE-2020-24387 — High (CVSS 7.5): An issue was discovered in the yh_create_session() function of yubihsm-shell through 2.0.2. The function does not…
CVE-2021-32489 — Medium (CVSS 4.4): An issue was discovered in the _send_secure_msg() function of Yubico yubihsm-shell through 2.0.3. The function does not…
CVE-2021-27217 — Medium (CVSS 4.4): An issue was discovered in the _send_secure_msg() function of Yubico yubihsm-shell through 2.0.3. The function does not…

All CVEs affecting Yubico Yubihsm-shell →

Other CWE-20 (Improper Input Validation) vulnerabilities

CVE-2026-48316 — Critical (CVSS 10.0): ColdFusion versions 2025.9, 2023.20 and earlier are affected by an Improper Input Validation vulnerability that could…
CVE-2026-48281 — Critical (CVSS 10.0): ColdFusion versions 2025.9, 2023.20 and earlier are affected by an Improper Input Validation vulnerability that could…
CVE-2026-48277 — Critical (CVSS 10.0): ColdFusion versions 2025.9, 2023.20 and earlier are affected by an Improper Input Validation vulnerability that could…
CVE-2026-48055 — Critical (CVSS 10.0): Streambert is a cross-platform Electron Desktop App to stream and download any video media. In versions 2.4.0 and…
CVE-2026-34910 — Critical (CVSS 10.0): A malicious actor with access to the network could exploit an Improper Input Validation vulnerability found in UniFi OS…
CVE-2026-33587 — Critical (CVSS 10.0): Lack of user input sanitisation in Open Notebook v1.8.3 allows the application user to execute Python code (and…

Browse all CWE-20 (Improper Input Validation) vulnerabilities →