Security readout for executives and security teams
Plain-English summary
CVE-2021-37456 is a stored cross-site scripting issue reported in NCH Axon PBX v2.22 and earlier. Malicious content could be saved through the blacklist IP address field and later run in a user's browser when viewed. Public sources do not provide CVSS scoring, patch details, or evidence of active exploitation.
Executive priority
Prioritize discovery and containment if NCH Axon PBX is in use, especially if management interfaces are exposed beyond trusted administrators. Urgency cannot be precisely ranked from the sources because severity, patch status, and exploitation status are not provided.
Technical view
The CVE describes stored XSS in NCH Axon PBX v2.22 and earlier via the blacklist IP address value. The source bundle provides a vendor product page and a public proof-of-concept reference, but no confirmed remediation version, authentication requirement, CWE mapping, or CVSS vector.
Likely exposure
Exposure is most likely limited to environments still running NCH Axon PBX v2.22 or earlier. Risk depends on whether the affected PBX interface is reachable by untrusted users and who can add or view blacklist IP entries. The sources do not quantify install base or exposure conditions.
Exploitation context
A public proof-of-concept reference exists, but the bundle does not show CISA KEV listing or active exploitation evidence. Treat exploitability as plausible for affected deployments, while avoiding assumptions about unauthenticated access or real-world compromise.
Researcher notes
The public record is sparse: product and version are named, stored XSS vector is named, and a proof-of-concept reference is cited. Missing details include CVSS, CWE, privilege requirements, affected route, fixed version, and vendor advisory language.
Mitigation direction
- Inventory NCH Axon PBX deployments and confirm exact versions.
- Check NCH guidance for fixed or supported Axon PBX releases.
- Restrict PBX management access to trusted networks or VPN.
- Review and remove suspicious blacklist IP entries.
- Monitor vendor and CVE records for remediation updates.
Validation and detection
- Confirm whether any Axon PBX instance is v2.22 or earlier.
- Review blacklist IP address records for unexpected markup or script-like content.
- Verify who can create and view blacklist entries.
- Check whether the PBX interface is internet-accessible.
- Document findings against CVE-2021-37456 for tracking.
Generated from the cited source records. This long-tail analysis has not been individually reviewed by a named human.
Conservative CVE-to-ATT&CK context
These mappings and lookup hints may be relevant to the vulnerability behavior, CWE, affected product, or exposure path. Glexia-inferred context is not an official MITRE, ATT&CK, CWE, or CVE Program mapping.
ATT&CK lookup starting points
Use these exact CWE pages and searches to review the Glexia ATT&CK library from this CVE's weakness and description context.
CVE-2021-37456 mapping review
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Open ATT&CK lookup- Severity
- Unknown
- CVSS
- Not scored
- Known Exploited
- No
- Published
CNA and ADP enrichment extracted from CVE v5
These fields come from the CVE record and ADP containers, not from Glexia's Take. They preserve time-varying source decisions such as CISA SSVC, KEV status, CVSS metrics, and provider references.
CVSS and timeline data
No CVSS vectors or timeline events were available in the normalized CVE source material.
Source materials
- CVE List V5 sourceCVE List V5
- https://www.nch.com.au/pbx/index.htmlCVE reference · x_refsource_MISC
- https://github.com/0xfml/poc/blob/main/NCH/Axon_2.22_XSS.mdCVE reference · x_refsource_MISC
Products and packages named in the record
CWE details
CWE links open Glexia weakness intelligence pages with official CWE context, developer remediation guidance, and related CVE mappings.