CVE-2021-40520: Airangel HSMX Gateway devices through 5.2.04 have Weak SSH Credentials.

Q: How do I fix CVE-2021-40520?

hsmx-app-25 firmware: upgrade to newer than 5.2.04; hsmx-app-100 firmware: upgrade to newer than 5.2.04; hsmx-app-1000 firmware: upgrade to newer than 5.2.04. Exact commands for each OS are on this page.

Q: Is CVE-2021-40520 being exploited?

CVE-2021-40520 is not on the CISA Known Exploited Vulnerabilities list at the time of the last update. Check again, as this can change.

Q: What does CVE-2021-40520 affect?

CVE-2021-40520 affects hsmx-app-25 firmware, hsmx-app-100 firmware, hsmx-app-1000 firmware. Severity is critical (CVSS 9.8). Airangel HSMX Gateway devices through 5.2.04 have Weak SSH Credentials.

Q: How urgent is CVE-2021-40520?

Priority 61/100. Critical severity; Public exploit reference; Remotely exploitable, no login, no user action

This week

CRITICAL 9.8REMOTEUPGRADEUPGRADEUPGRADE

CVE-2021-40520 is a critical-severity flaw (CVSS 9.8) affecting hsmx-app-25 firmware, hsmx-app-100 firmware, hsmx-app-1000 firmware. Below: why it ranks where it does, which versions are affected, what to do, and the exact commands.

Airangel HSMX Gateway devices through 5.2.04 have Weak SSH Credentials.

Why this priority

Critical severity
Public exploit reference
Remotely exploitable, no login, no user action

A fixed release or distro patch exists.

Risk facts

CVSS score	9.8 (Critical)
Attack vector	Network (remote)
Attack complexity	Low
Privileges needed	None
User interaction	None
EPSS exploit chance	1.2% (top 32%)
CISA exploited list	No
Weakness	CWE-521
Published	2021-11-10
Last modified	2026-06-17

Publisher (CNA): MITRE · Vendor: airangel

Last updated 2026-06-17 · Sources: CVE Program, NVD, CISA KEV, EPSS and vendor advisories · How we score

Am I affected?

Timeline

2021-11-10 17:15 UTCPublished CVE record published
2026-06-17 04:07 UTCUpdated Record last modified

airangel hsmx-app-25 firmware UPGRADE

Affected: <= 5.2.04

Fixed in: newer than 5.2.04

Safe to downgrade to: no unaffected older release

Check your OS release

cat /etc/os-release; uname -r

Debian / Ubuntu

sudo apt update && sudo apt full-upgrade

RHEL / Amazon Linux / Fedora

sudo dnf upgrade --refresh

Windows

Install the latest cumulative update from Windows Update

If no patch exists yet

OS downgrades are not safe. Apply the vendor mitigation from the advisory and restrict exposure.

airangel hsmx-app-100 firmware UPGRADE

Affected: <= 5.2.04

Fixed in: newer than 5.2.04

Safe to downgrade to: no unaffected older release

Check your OS release

cat /etc/os-release; uname -r

Debian / Ubuntu

sudo apt update && sudo apt full-upgrade

RHEL / Amazon Linux / Fedora

sudo dnf upgrade --refresh

Windows

Install the latest cumulative update from Windows Update

If no patch exists yet

OS downgrades are not safe. Apply the vendor mitigation from the advisory and restrict exposure.

airangel hsmx-app-1000 firmware UPGRADE

Affected: <= 5.2.04

Fixed in: newer than 5.2.04

Safe to downgrade to: no unaffected older release

Check your OS release

cat /etc/os-release; uname -r

Debian / Ubuntu

sudo apt update && sudo apt full-upgrade

RHEL / Amazon Linux / Fedora

sudo dnf upgrade --refresh

Windows

Install the latest cumulative update from Windows Update

If no patch exists yet

OS downgrades are not safe. Apply the vendor mitigation from the advisory and restrict exposure.

airangel hsmx-app-5000 firmware UPGRADE

Affected: <= 5.2.04

Fixed in: newer than 5.2.04

Safe to downgrade to: no unaffected older release

Check your OS release

cat /etc/os-release; uname -r

Debian / Ubuntu

sudo apt update && sudo apt full-upgrade

RHEL / Amazon Linux / Fedora

sudo dnf upgrade --refresh

Windows

Install the latest cumulative update from Windows Update

If no patch exists yet

OS downgrades are not safe. Apply the vendor mitigation from the advisory and restrict exposure.

airangel hsmx-app-20000 firmware UPGRADE

Affected: <= 5.2.04

Fixed in: newer than 5.2.04

Safe to downgrade to: no unaffected older release

Check your OS release

cat /etc/os-release; uname -r

Debian / Ubuntu

sudo apt update && sudo apt full-upgrade

RHEL / Amazon Linux / Fedora

sudo dnf upgrade --refresh

Windows

Install the latest cumulative update from Windows Update

If no patch exists yet

OS downgrades are not safe. Apply the vendor mitigation from the advisory and restrict exposure.

Verify at the official source NVD · CVE Program · Report a problem with this page
Scores and fixes here are computed automatically from those and other public sources. Confirm with the vendor advisory before changing production systems.

Quick answers

How do I fix CVE-2021-40520?

hsmx-app-25 firmware: upgrade to newer than 5.2.04; hsmx-app-100 firmware: upgrade to newer than 5.2.04; hsmx-app-1000 firmware: upgrade to newer than 5.2.04. Exact commands for each OS are on this page.

Is CVE-2021-40520 being exploited?

CVE-2021-40520 is not on the CISA Known Exploited Vulnerabilities list at the time of the last update. Check again, as this can change.

What does CVE-2021-40520 affect?

CVE-2021-40520 affects hsmx-app-25 firmware, hsmx-app-100 firmware, hsmx-app-1000 firmware. Severity is critical (CVSS 9.8). Airangel HSMX Gateway devices through 5.2.04 have Weak SSH Credentials.

How urgent is CVE-2021-40520?

Priority 61/100. Critical severity; Public exploit reference; Remotely exploitable, no login, no user action

Related CVEs

CVE-2021-40521 CRITICAL 9.8 UPGRADE UPGRADE Airangel HSMX Gateway devices through 5.2.04 allow Remote Code Execution.
CVE-2021-40519 CRITICAL 10.0 UPGRADE UPGRADE Airangel HSMX Gateway devices through 5.2.04 have Hard-coded Database Credentials.
CVE-2021-40518 MEDIUM 6.5 UPGRADE UPGRADE Airangel HSMX Gateway devices through 5.2.04 allow CSRF.
CVE-2021-40517 MEDIUM 5.4 UPGRADE UPGRADE Airangel HSMX Gateway devices through 5.2.04 is vulnerable to stored Cross Site Scripting

References

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