CVE-2021-37456: Cross Site Scripting (XSS) exists in NCH Axon PBX v2.22 and earlier via the blacklist IP address (stored).

Q: How do I fix CVE-2021-37456?

axon pbx: upgrade to newer than 2.22. Exact commands for each OS are on this page.

Q: Is CVE-2021-37456 being exploited?

CVE-2021-37456 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-2021-37456 affect?

CVE-2021-37456 affects axon pbx. Severity is medium (CVSS 5.4). Cross Site Scripting (XSS) exists in NCH Axon PBX v2.22 and earlier via the blacklist IP address (stored).

Q: How urgent is CVE-2021-37456?

Priority 36/100. Public exploit reference

Routine

MEDIUM 5.4UPGRADE

CVE-2021-37456 is a medium-severity flaw (CVSS 5.4) affecting axon pbx. Below: why it ranks where it does, which versions are affected, what to do, and the exact commands.

Cross Site Scripting (XSS) exists in NCH Axon PBX v2.22 and earlier via the blacklist IP address (stored).

Why this priority

Public exploit reference

A fixed release or distro patch exists.

Risk facts

CVSS score	5.4 (Medium)
Attack vector	Network (remote)
Attack complexity	Low
Privileges needed	Low
User interaction	Required
EPSS exploit chance	0.6% (top 52%)
CISA exploited list	No
Weakness	CWE-79
Published	2021-07-25
Last modified	2026-06-17

Publisher (CNA): MITRE · Vendor: nchsoftware

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

Am I affected?

Timeline

2021-07-25 21:15 UTCPublished CVE record published
2026-06-17 04:00 UTCUpdated Record last modified

nchsoftware axon pbx UPGRADE

Affected: <= 2.22

Fixed in: newer than 2.22

Safe to downgrade to: no unaffected older release

1. Check installed version

apt-cache policy axon-pbx || rpm -q axon-pbx || axon-pbx --version

2. UPGRADE to newer than 2.22 (Debian / Ubuntu)

sudo apt update && sudo apt install --only-upgrade axon-pbx

2. UPGRADE (RHEL / Amazon Linux / Fedora)

sudo dnf upgrade axon-pbx

Note

Distros often backport fixes without changing the version number. Confirm with the distro advisory or changelog.

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-2021-37456?

axon pbx: upgrade to newer than 2.22. Exact commands for each OS are on this page.

Is CVE-2021-37456 being exploited?

CVE-2021-37456 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-2021-37456 affect?

CVE-2021-37456 affects axon pbx. Severity is medium (CVSS 5.4). Cross Site Scripting (XSS) exists in NCH Axon PBX v2.22 and earlier via the blacklist IP address (stored).

How urgent is CVE-2021-37456?

Priority 36/100. Public exploit reference

Related CVEs

CVE-2021-37462 MEDIUM 5.4 UPGRADE Cross Site Scripting (XSS) exists in NCH Axon PBX v2.22 and earlier via /ipblacklist?errorip= (reflected).
CVE-2021-37461 MEDIUM 5.4 UPGRADE Cross Site Scripting (XSS) exists in NCH Axon PBX v2.22 and earlier via /extensionsinstruction?id= (reflected)
CVE-2021-37460 MEDIUM 5.4 UPGRADE Cross Site Scripting (XSS) exists in NCH Axon PBX v2.22 and earlier via /planprop?id= (reflected).
CVE-2021-37459 MEDIUM 5.4 UPGRADE Cross Site Scripting (XSS) exists in NCH Axon PBX v2.22 and earlier via the customer name field (stored).
CVE-2021-37458 MEDIUM 5.4 UPGRADE Cross Site Scripting (XSS) exists in NCH Axon PBX v2.22 and earlier via the primary phone field (stored).

References

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