CVE-2025-47188: Mitel SIP Phones RCE Vulnerability

CVE-2025-47188 Overview

CVE-2025-47188 is an unauthenticated command injection vulnerability affecting Mitel 6800 Series, 6900 Series, and 6900w Series SIP Phones, along with the 6970 Conference Unit. The flaw stems from insufficient parameter sanitization in the phone firmware, classified under [CWE-77] Improper Neutralization of Special Elements Used in a Command. A remote attacker can send crafted input over the network to execute arbitrary commands within the context of the phone. Successful exploitation exposes sensitive configuration data, permits modification of device settings, and can disrupt device availability or operation.

Critical Impact
An unauthenticated network attacker can execute arbitrary commands on affected Mitel SIP phones, leading to configuration disclosure, tampering, and disruption of voice communications infrastructure.

Affected Products

Mitel 6800 Series SIP Phones through 6.4 SP4 (R6.4.0.4006)
Mitel 6900 Series and 6900w Series SIP Phones through 6.4 SP4 (R6.4.0.4006)
Mitel 6970 Conference Unit through 6.4 SP4 (R6.4.0.4006) or version V1 R0.1.0

Discovery Timeline

2025-08-07 - CVE-2025-47188 published to NVD
2026-06-17 - Last updated in NVD database

Technical Details for CVE-2025-47188

Vulnerability Analysis

The vulnerability resides in the request handling logic exposed by the Mitel SIP phone firmware. User-supplied parameters reach an underlying command execution path without adequate sanitization or validation. An unauthenticated attacker with network access to the phone can inject shell metacharacters into the vulnerable parameter and cause the device to execute attacker-controlled commands.

The attack requires no privileges and no user interaction. Because the phones frequently sit on trusted VoIP VLANs with reachability to internal services, a compromised phone provides a foothold for lateral movement, eavesdropping on call metadata, or manipulation of SIP signaling. According to the Mitel Security Advisory MISA-2025-0004, the impact is limited to the phone context but includes disclosure and modification of sensitive configuration data.

Root Cause

The root cause is improper neutralization of special elements passed to a downstream command interpreter [CWE-77]. Input received over the network is concatenated into a command string executed by the firmware without escaping or allow-listing. This class of flaw commonly appears in embedded web management interfaces and provisioning handlers.

Attack Vector

The attack vector is network-based. An attacker who can reach the phone's management or provisioning interface sends a crafted HTTP request or protocol message containing shell metacharacters in a vulnerable parameter. The firmware executes the injected commands with the privileges of the handling service on the device. No authentication is required, which increases exposure on flat networks where SIP phones are reachable from user endpoints.

No verified public proof-of-concept code has been released. Refer to the Mitel Security Advisories portal for authoritative technical details.

Detection Methods for CVE-2025-47188

Indicators of Compromise

Unexpected outbound network connections originating from SIP phone IP addresses to non-VoIP destinations
Anomalous HTTP or provisioning requests targeting phone management interfaces containing shell metacharacters such as ;, |, `, or $()
Unexplained changes to phone configuration files, firmware settings, or call routing parameters
SIP phones initiating scans or connections against internal services outside normal telephony traffic patterns

Detection Strategies

Deploy network intrusion detection signatures that flag command injection payloads in HTTP requests directed at Mitel phone management endpoints
Baseline expected traffic patterns for SIP phones and alert on deviations, particularly outbound connections to non-telephony infrastructure
Inspect phone provisioning server logs for malformed or suspicious parameter values submitted by unauthenticated clients

Monitoring Recommendations

Forward VoIP infrastructure logs and phone syslog output to a centralized logging platform for correlation and retention
Monitor VLAN boundaries between user endpoints and the VoIP network for unauthorized east-west traffic to phone management ports
Track firmware versions across the phone fleet and alert on devices running versions at or below 6.4 SP4 (R6.4.0.4006)

How to Mitigate CVE-2025-47188

Immediate Actions Required

Inventory all Mitel 6800, 6900, 6900w Series SIP Phones and 6970 Conference Units, recording firmware versions
Apply the fixed firmware release published by Mitel in advisory MISA-2025-0004 as soon as it is available for your model
Restrict network access to phone management and provisioning interfaces using ACLs, firewall rules, or dedicated VoIP VLAN segmentation
Rotate any credentials or configuration secrets stored on devices that were reachable from untrusted networks prior to patching

Patch Information

Mitel has published remediation guidance in Mitel Security Advisory MISA-2025-0004. Administrators should upgrade affected devices to the fixed firmware release referenced in that advisory. Versions through 6.4 SP4 (R6.4.0.4006) for the 6800, 6900, 6900w, and 6970 product lines, and V1 R0.1.0 for the 6970 Conference Unit, are affected.

Workarounds

Isolate SIP phones on a dedicated VoIP VLAN with strict access control lists blocking untrusted sources from reaching phone HTTP and provisioning ports
Disable remote management interfaces on phones where they are not operationally required
Enforce network-level authentication such as 802.1X on switch ports to prevent unauthorized devices from reaching the phone network segment

bash

# Example ACL restricting access to phone management interface to a jump host only
access-list VOIP_MGMT permit tcp host 10.10.5.10 10.20.30.0 0.0.0.255 eq 80
access-list VOIP_MGMT permit tcp host 10.10.5.10 10.20.30.0 0.0.0.255 eq 443
access-list VOIP_MGMT deny   tcp any 10.20.30.0 0.0.0.255 eq 80
access-list VOIP_MGMT deny   tcp any 10.20.30.0 0.0.0.255 eq 443
access-list VOIP_MGMT permit ip any any