CVE-2021-39243: Cross-Site Request Forgery (CSRF) exists on Altus Nexto, Nexto Xpress, and Hadron Xtorm devices via any CGI en

Routine

MEDIUM 6.5MITIGATEMITIGATEMITIGATE

CVE-2021-39243 is a medium-severity flaw (CVSS 6.5) affecting nexto nx3003 firmware, nexto nx3004 firmware, nexto nx3005 firmware. Below: why it ranks where it does, which versions are affected, what to do, and the exact commands.

Cross-Site Request Forgery (CSRF) exists on Altus Nexto, Nexto Xpress, and Hadron Xtorm devices via any CGI endpoint. This affects Nexto NX3003 1.8.11.0, Nexto NX3004 1.8.11.0, Nexto NX3005 1.8.11.0, Nexto NX3010 1.8.3.0, Nexto NX3020 1.8.3.0, Nexto NX3030 1.8.3.0, Nexto NX5100 1.8.11.0, Nexto NX5101 1.8.11.0, Nexto NX5110 1.1.2.8, Nexto NX5210 1.1.2.8, Nexto Xpress XP300 1.8.11.0, Nexto Xpress XP315 1.8.11.0, Nexto Xpress XP325 1.8.11.0, Nexto X

Why this priority

Public exploit reference

No fix is published yet: follow the downgrade or mitigation steps.

Risk facts

CVSS score	6.5 (Medium)
Attack vector	Network (remote)
Attack complexity	Low
Privileges needed	None
User interaction	Required
EPSS exploit chance	0.5% (top 55%)
CISA exploited list	No
Weakness	CWE-352
Published	2021-08-23
Last modified	2026-06-17

Publisher (CNA): MITRE · Vendor: altus

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

Am I affected?

Timeline

2021-08-23 05:15 UTCPublished CVE record published
2026-06-17 04:03 UTCUpdated Record last modified

altus nexto nx3003 firmware MITIGATE

Affected: 1.8.11.0

Fixed in: no fixed release known

Safe to downgrade to: a release before 1.8.11.0

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.

altus nexto nx3004 firmware MITIGATE

Affected: 1.8.11.0

Fixed in: no fixed release known

Safe to downgrade to: a release before 1.8.11.0

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.

altus nexto nx3005 firmware MITIGATE

Affected: 1.8.11.0

Fixed in: no fixed release known

Safe to downgrade to: a release before 1.8.11.0

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.

altus nexto nx3010 firmware MITIGATE

Affected: 1.8.3.0

Fixed in: no fixed release known

Safe to downgrade to: a release before 1.8.3.0

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.

altus nexto nx3020 firmware MITIGATE

Affected: 1.8.3.0

Fixed in: no fixed release known

Safe to downgrade to: a release before 1.8.3.0

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.

altus nexto nx3030 firmware MITIGATE

Affected: 1.8.3.0

Fixed in: no fixed release known

Safe to downgrade to: a release before 1.8.3.0

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-2021-39243?

nexto nx3003 firmware: mitigate or apply the listed mitigation; nexto nx3004 firmware: mitigate or apply the listed mitigation; nexto nx3005 firmware: mitigate or apply the listed mitigation. Exact commands for each OS are on this page.

Is CVE-2021-39243 being exploited?

CVE-2021-39243 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-2021-39243 affect?

CVE-2021-39243 affects nexto nx3003 firmware, nexto nx3004 firmware, nexto nx3005 firmware. Severity is medium (CVSS 6.5). Cross-Site Request Forgery (CSRF) exists on Altus Nexto, Nexto Xpress, and Hadron Xtorm devices via any CGI endpoint. This affects Nexto NX3003 1.8.11.0, Nexto NX3004 1.8.11.0, Nexto NX3005 1.8.11.0, Nexto NX3010 1.8.3.0, Nexto NX3020 1.8.3

How urgent is CVE-2021-39243?

Priority 39/100. Public exploit reference

Related CVEs

CVE-2021-39245 HIGH 7.5 MITIGATE MITIGATE Hardcoded .htaccess Credentials for getlogs.cgi exist on Altus Nexto, Nexto Xpress, and Hadron Xtorm devices
CVE-2021-39244 HIGH 8.8 MITIGATE MITIGATE Authenticated Semi-Blind Command Injection (via Parameter Injection) exists on Altus Nexto, Nexto Xpress, and

References

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