Which versions of FreePBX are affected by CVE-2026-46376?

FreePBX User Control Panel (UCP) versions 15.0.42 through 17.0.6 contain an authentication bypass vulnerability allowing remote attackers to access user accounts using hard-coded initial credentials…. A patch is available.

How to fix or mitigate CVE-2026-46376?

Within 24 hours: Inventory all FreePBX deployments and identify instances running affected versions (15.0.42-16.0.44 or 17.0.0-17.0.6); verify whether hard-coded initial credentials have been rotated since UCP feature enablement. Within 7 days: For affected instances, implement network-level access controls restricting UCP to authorized administrator IPs only, enable detailed access logging, and contact FreePBX vendor to confirm patch availability timeline and interim recommendations. Within 30 days: Deploy any released patches to affected versions; establish upgrade timeline for unpatched systems; consider disabling UCP feature if business operations permit.

FreePBX CVE-2026-46376

Q: What is the CVSS score of CVE-2026-46376?

CVE-2026-46376 has a CVSS 4.0 base score of 9.3 (Critical). CVSS vector: CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:H/VI:H/VA:N/SC:N/SI:N/SA:N/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X. EPSS exploitation probability: 0.1%.

EUVD-2026-33295 CRITICAL

Use of Hard-coded Credentials (CWE-798)

2026-05-29 GitHub_M

Authentication Bypass Security Reporting

9.3

CVSS 4.0 · GitHub Advisory

Severity by source

GitHub Advisory PRIMARY

9.3 CRITICAL

CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:H/VI:H/VA:N/SC:N/SI:N/SA:N/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X

Primary rating from GitHub Advisory · only source for this CVE.

CVSS VectorGitHub Advisory

CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:H/VI:H/VA:N/SC:N/SI:N/SA:N/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X

Attack Vector

Network

Attack Complexity

Low

Privileges Required

None

User Interaction

None

Scope

Lifecycle Timeline

Patch available

May 29, 2026 - 15:01 EUVD

Analysis Generated

May 29, 2026 - 14:32 vuln.today

CVSS changed

May 29, 2026 - 14:22 NVD

9.3 (CRITICAL)

DescriptionGitHub Advisory

FreePBX is an open source IP PBX. From 15.0.42 to before 16.0.45 and 17.0.7, unauthenticated users may be able to access the User Control Panel (UCP) using hard-coded initial template credentials if these were not immediately changed by the Administrator who enabled UCP. Authenticated access to ACP is required for the initial setup of UCP generic templates, but after that, without further steps by the admin, unauthenticated users may be able to gain access. This vulnerability is fixed in 16.0.45 and 17.0.7.

AnalysisAI

Authentication bypass in FreePBX User Control Panel (UCP) versions 15.0.42 through 16.0.44 and 17.0.0 through 17.0.6 allows remote unauthenticated attackers to access UCP accounts using hard-coded initial template credentials when administrators fail to rotate them after enabling the feature. With a CVSS 4.0 score of 9.3 and CWE-798 (Use of Hard-coded Credentials), the flaw exposes high-confidentiality and high-integrity impact to the affected component, though no public exploit identified at time of analysis.

Technical ContextAI

FreePBX is a widely deployed open-source GUI front-end for the Asterisk VoIP/PBX engine, used to manage telephony, voicemail, IVR, and user features. The vulnerable component is the User Control Panel (UCP), the end-user web portal allowing users to manage their voicemail, call recordings, contacts, and call routing. CWE-798 (Use of Hard-coded Credentials) is the root cause: the initial UCP generic template ships with fixed credentials that are configured during ACP setup but persist as a valid login path until an administrator explicitly rotates or removes them. Because the credentials are static and known (or discoverable via source code), any party reaching the UCP login can authenticate as the template user. The affected CPE is cpe:2.3:a:freepbx:security-reporting:*, corresponding to FreePBX's security-reporting module that issued the advisory.

RemediationAI

Vendor-released patches are available in FreePBX 16.0.45 and 17.0.7, and operators should upgrade to one of these versions immediately following the GitHub Security Advisory at https://github.com/FreePBX/security-reporting/security/advisories/GHSA-m55x-h47x-v3gx. Administrators on 15.x should plan migration to a fixed branch since no 15.x fix is named in the advisory. As a workaround pending the upgrade, administrators should disable UCP via the FreePBX Module Admin (which removes the end-user portal feature for all users), or, if UCP must remain enabled, immediately rotate or delete the initial UCP generic template credentials provisioned during ACP setup and audit existing UCP user accounts for unauthorized additions; additionally, restrict UCP web access to trusted internal networks via reverse-proxy ACLs or firewall rules, accepting that this prevents legitimate remote user portal access until the patch is applied.