What’s Vulnerable › Vulnerabilities

CVE-2021-43405

• Severity: high (CVSS 8.8 v3.1)
• Exploited in the wild: not listed in CISA KEV
• EPSS: 35.6% probability of exploitation in the next 30 days
• Public exploit or detection template: yes
• Published: 2021-11-05 · updated 2026-06-17

Description

An issue was discovered in FusionPBX before 4.5.30. The fax_extension may have risky characters (it is not constrained to be numeric).

Affected products

• fusionpbx: before 4.5.30 — fixed in 4.5.30

How to fix

Upgrade to a fixed version: fusionpbx 4.5.30. Check the vendor advisory for mitigations.

References

• http://packetstormsecurity.com/files/164795/FusionPBX-4.5.29-Remote-Code-Execution.html
• https://github.com/fusionpbx/fusionpbx/commit/2d2869c1a1e874c46a8c3c5475614ce769bbbd59
• http://packetstormsecurity.com/files/164795/FusionPBX-4.5.29-Remote-Code-Execution.html
• https://github.com/fusionpbx/fusionpbx/commit/2d2869c1a1e874c46a8c3c5475614ce769bbbd59

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