CVE-2021-40520

Exp

Airangel HSMX Gateway devices through 5.2.04 have Weak SSH Credentials.

Published: 2021-11-10 Last update: 2024-11-21 Assigner: [email protected] Source: [email protected]
NVD Status：Modified，CVE State: published
View at NVD, CVE.org, EUVD

CVE-2021-40520 is rated High Exploit Risk (76.8/100): CVSS Critical severity, with medium exploitation likelihood (EPSS 1.15%). 1 public exploit reference(s) are indexed (Exploit-DB). 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.

Public exploit references (Exploit-DB) for CVE-2021-40520

EDB-ID Source Kind Published Link
— nvd_ref exploit_tag Exploit-DB ↗

Exploit prediction scoring system (EPSS) score for CVE-2021-40520

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 0.38% 1.15% +0.76%
2 2025-03-30 0.75% 0.38% -0.36%
3 2025-03-29 — 0.75% —

Full EPSS history (13 records total)

Common vulnerability scoring system (CVSS) metrics for CVE-2021-40520

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]
5.0 2.0 MEDIUM
AV:N/AC:L/Au:N/C:P/I:N/A:N 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:N)
No integrity impact.
Availability impact (A:N)
No availability impact.
 10.0 2.9 [email protected]

Weakness enumeration for CVE-2021-40520

Affected software / configurations for CVE-2021-40520

Vendor Product Version Raw CPE
airangel hsmx-app-25_firmware <= 5.2.04 cpe:2.3:o:airangel:hsmx-app-25_firmware:*:*:*:*:*:*:*:*
airangel hsmx-app-100_firmware <= 5.2.04 cpe:2.3:o:airangel:hsmx-app-100_firmware:*:*:*:*:*:*:*:*
airangel hsmx-app-1000_firmware <= 5.2.04 cpe:2.3:o:airangel:hsmx-app-1000_firmware:*:*:*:*:*:*:*:*
airangel hsmx-app-5000_firmware <= 5.2.04 cpe:2.3:o:airangel:hsmx-app-5000_firmware:*:*:*:*:*:*:*:*
airangel hsmx-app-20000_firmware <= 5.2.04 cpe:2.3:o:airangel:hsmx-app-20000_firmware:*:*:*:*:*:*:*:*

References for CVE-2021-40520

URL Tags
http://etizazmohsin.com/hsmx.html#ssh Exploit Third Party Advisory
https://airangel.com/hsmx-gateway/ Product
cvelogic Threat Intelligence