How severe is CVE-2021-40520?

CVE-2021-40520 has a CVSS 3.x base score of 9.8, rated critical severity. It is exploitable over network with low attack complexity, requires no privileges and no user interaction. Impact on confidentiality is high, integrity high, and availability high.

Is CVE-2021-40520 being actively exploited?

It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 1% (63rd percentile), an estimate of the probability of exploitation in the next 30 days.

What products are affected by CVE-2021-40520?

CVE-2021-40520 primarily affects Airangel Hsmx-app-25 Firmware. In total, 5 product configurations (CPEs) are listed as vulnerable; see the affected-products list for the exact versions.

How do I fix CVE-2021-40520?

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

When was CVE-2021-40520 published?

CVE-2021-40520 was published on 2021-11-10 and last updated on 2026-06-17.

CVE-2021-40520

CVE-2021-40520 is a critical-severity vulnerability in Airangel Hsmx-app-25 Firmware with a CVSS 3.x base score of 9.8. 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-521.

Key facts

Severity: Critical (CVSS 3.x base score 9.8)
CVSS v2: 5.0
EPSS exploit prediction: 1% (63rd percentile)
Actively exploited: Not listed in CISA KEV
Weakness: CWE-521
Affected product: Airangel Hsmx-app-25 Firmware
Published: 2021-11-10
Last modified: 2026-06-17

Description

Airangel HSMX Gateway devices through 5.2.04 have Weak SSH Credentials.

Frequently asked questions

What is CVE-2021-40520?: Airangel HSMX Gateway devices through 5.2.04 have Weak SSH Credentials.
How severe is CVE-2021-40520?: CVE-2021-40520 has a CVSS 3.x base score of 9.8, rated critical severity. It is exploitable over network with low attack complexity, requires no privileges and no user interaction. Impact on confidentiality is high, integrity high, and availability high.
Is CVE-2021-40520 being actively exploited?: It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 1% (63rd percentile), an estimate of the probability of exploitation in the next 30 days.
What products are affected by CVE-2021-40520?: CVE-2021-40520 primarily affects Airangel Hsmx-app-25 Firmware. In total, 5 product configurations (CPEs) are listed as vulnerable; see the affected-products list for the exact versions.
How do I fix CVE-2021-40520?: Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround. Given its critical severity, prioritise patching exposed systems.
When was CVE-2021-40520 published?: CVE-2021-40520 was published on 2021-11-10 and last updated on 2026-06-17.

References

Affected products (5)

cpe:2.3:o:airangel:hsmx-app-25_firmware:*:*:*:*:*:*:*:*
cpe:2.3:o:airangel:hsmx-app-100_firmware:*:*:*:*:*:*:*:*
cpe:2.3:o:airangel:hsmx-app-1000_firmware:*:*:*:*:*:*:*:*
cpe:2.3:o:airangel:hsmx-app-5000_firmware:*:*:*:*:*:*:*:*
cpe:2.3:o:airangel:hsmx-app-20000_firmware:*:*:*:*:*:*:*:*

More vulnerabilities in Airangel Hsmx-app-25 Firmware

CVE-2021-40519 — Critical (CVSS 10.0): Airangel HSMX Gateway devices through 5.2.04 have Hard-coded Database Credentials.
CVE-2021-40521 — Critical (CVSS 9.8): Airangel HSMX Gateway devices through 5.2.04 allow Remote Code Execution.
CVE-2021-40518 — Medium (CVSS 6.5): Airangel HSMX Gateway devices through 5.2.04 allow CSRF.
CVE-2021-40517 — Medium (CVSS 5.4): Airangel HSMX Gateway devices through 5.2.04 is vulnerable to stored Cross Site Scripting. XSS Payload is placed in the…

All CVEs affecting Airangel Hsmx-app-25 Firmware →

Other CWE-521 (Weak Password Requirements) vulnerabilities

CVE-2026-25715 — Critical (CVSS 9.8): The web management interface of the device allows the administrator username and password to be set to blank values.…
CVE-2025-53963 — Critical (CVSS 9.8): An issue was discovered on Thermo Fisher Ion Torrent OneTouch 2 INS1005527 devices. They run an SSH server accessible…
CVE-2025-63747 — Critical (CVSS 9.8): QaTraq 6.9.2 ships with administrative account credentials which are enabled in default installations and permit…
CVE-2025-12552 — Critical (CVSS 9.8): Insufficient Password Policy.This issue affects BLU-IC2: through 1.19.5; BLU-IC4: through 1.19.5.
CVE-2025-11200 — Critical (CVSS 9.8): MLflow Weak Password Requirements Authentication Bypass Vulnerability. This vulnerability allows remote attackers to…
CVE-2025-12364 — Critical (CVSS 9.8): Weak Password Policy.This issue affects BLU-IC2: through 1.19.5; BLU-IC4: through 1.19.5.

Browse all CWE-521 (Weak Password Requirements) vulnerabilities →