CVE-2025-66039: FreePBX framework · Improper Authentication
Affects FreePBX frameworkSource CVE Database V5
Not known to be exploited · public exploit available (Metasploit) · CVSS 9.3 Critical : upgrade to 16.0.44 as a priority.
Data as of 26 Oct 2026, 06:26 UTC
- EPSS
- 3.3% chance of exploitation in 30 days – higher than 88% of CVEsExploit Prediction Scoring System: the likelihood attackers will use this flaw soon.
- Patch
- Available – fixed in 16.0.44
CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:H/VI:H/VA:H/SC:N/SI:N/SA:NExploitation evidence
Disclosed: evidence found.
CVE published 9 Dec 2025
Detectable: no evidence on record.
No public nuclei template indexed
Weaponised: evidence found.
Exploited in the wildExploited: no evidence on record.
Not in CISA KEV and no source reports exploitation
Observed by OffSeq MirageSeen by Mirage: no evidence on record.
No attack traffic recorded by OffSeq Mirage sensors
A missing step is not evidence of safety. Sources: cve.org (opens in a new tab), the Metasploit, Exploit-DB and nuclei-templates index as of 2026-10-26.
What to do
Upgrade freepbx/framework to 16.0.44.
Affected software
| Product | Affected | Fixed in |
|---|---|---|
GitHubfreepbx/frameworkpkg:github/freepbx/frameworkOther threats | Affected
| Fixed in
|
Check your own hosts for these packages with threat-finder (opens in a new tab), our free open-source scanner.
AI-suggested
To mitigate this vulnerability, organizations should immediately upgrade FreePBX Endpoint Manager to versions 16.0.44 or 17.0.23 or later, where the authentication bypass flaw is fixed. Until patches can be applied, restrict network access to the FreePBX management interface by implementing strict firewall rules limiting access to trusted IP addresses only. Employ network segmentation to isolate telephony management systems from general user networks and the internet. Enable and enforce strong authentication mechanisms outside of the vulnerable "webserver" authentication mode, if possible. Monitor logs for suspicious Authorization header values or unusual session activity indicative of exploitation attempts. Conduct regular security audits and vulnerability scans on telephony infrastructure. Additionally, consider deploying intrusion detection/prevention systems (IDS/IPS) tuned to detect anomalous HTTP header manipulations targeting FreePBX endpoints. Maintain up-to-date backups of telephony configurations to enable rapid recovery if compromise occurs.
Description
FreePBX Endpoint Manager is a module for managing telephony endpoints in FreePBX systems. Versions are vulnerable to authentication bypass when the authentication type is set to "webserver." When providing an Authorization header with an arbitrary value, a session is associated with the target user regardless of valid credentials. This issue is fixed in versions 16.0.44 and 17.0.23.