CVE-2024-55550: Mitel MiCollab Path Traversal Vulnerability

CVE-2024-55550 is a path traversal vulnerability in Mitel MiCollab that lets an authenticated attacker with administrative privileges read local files on the system because of insufficient input sanitization. It can be chained with CVE-2024-41713, which enables an unauthenticated remote attacker to read arbitrary files on the server. The vulnerability has been used in ransomware activity, so organizations running MiCollab should treat it as a high-priority risk to confidentiality and overall system integrity.

Defenders need clear inventory, rapid patching or mitigation per vendor guidance, and monitoring for signs of file-read abuse. Confirm every version, configuration detail, and remediation step against the official Mitel advisory before acting.

How it works

This issue is classified as CWE-22 (path traversal). Path traversal flaws arise when an application fails to properly sanitize user-supplied input that is used to construct file-system paths. An attacker can insert sequences that navigate outside the intended directory and reach sensitive local files.

In this case, an authenticated administrative user can exploit the insufficient sanitization to read files that should remain inaccessible. The CISA summary notes that the vulnerability can be chained with CVE-2024-41713. That second issue allows an unauthenticated remote attacker to read arbitrary files, so the combination can escalate from a privileged local-file read into broader unauthenticated remote file disclosure. Exact request formats, parameters, or payloads are not provided here; treat any public proof-of-concept material with caution and validate behavior only against the vendor advisory.

Am I affected? How to find it in your systems

Mitel MiCollab is collaboration and unified-communications software commonly deployed on-premises or in managed environments to support voice, messaging, and conferencing. It typically runs on dedicated application servers or virtual machines that are reachable by administrators and, in some configurations, by remote users.

• Inventory all hosts and virtual machines that host Mitel MiCollab components. Check asset-management databases, CMDB records, and network scans for MiCollab-related services or ports.
• Identify the installed product version and any applied hotfixes. Compare them directly against the versions listed as affected in the Mitel advisory for CVE-2024-55550; do not rely on secondary sources.
• Review administrative access controls and authentication logs for accounts that hold elevated privileges on the MiCollab system.
• Look for telemetry that may indicate exploitation: unusual file-read operations outside normal application directories, unexpected path strings containing traversal sequences, or anomalous administrative sessions that coincide with large or sensitive file access. Correlate application logs, web-server access logs, and host-based file-integrity or process-monitoring data.

If inventory is incomplete, treat any reachable MiCollab instance as potentially affected until the vendor advisory confirms otherwise.

How to remediate

The primary remediation is to apply the mitigations or updates supplied by Mitel for CVE-2024-55550. Follow the vendor instructions exactly; CISA’s required action is to apply those mitigations or discontinue use of the product if mitigations are unavailable.

• Obtain the official advisory and any associated patches or configuration guidance from Mitel.
• Test the update in a non-production environment if possible, then deploy it to production systems during a controlled maintenance window.
• After patching, re-verify that the previously vulnerable input paths no longer accept traversal sequences and that administrative file-access controls behave as expected.
• As general hardening for this class of weakness, enforce strict input validation and canonicalization on any path-related parameters, run the application under least-privilege accounts, and restrict the set of directories the process can access.

Document the remediation steps and retain evidence of the applied update for audit purposes.

If you can't patch immediately

When an immediate vendor update cannot be applied, reduce exposure with compensating controls while you prepare the permanent fix.

• Segment the MiCollab hosts so that only necessary management and user networks can reach them; block direct internet exposure of administrative interfaces.
• Deploy virtual patching or web-application firewall rules that detect and block common path-traversal patterns in requests directed at the MiCollab application. Tune rules carefully to avoid false positives and confirm coverage against the vendor’s description of the issue.
• Temporarily disable or tightly restrict any non-essential features or administrative interfaces that accept path-related input, if the product configuration allows it.
• Increase monitoring and alerting on file-access events, administrative logins, and anomalous process behavior. Retain logs long enough to support forensic review if ransomware activity is later suspected.
• Limit the number of accounts that possess administrative privileges on the system and enforce multi-factor authentication for those accounts.

These measures lower risk but do not eliminate the vulnerability; schedule the official remediation as soon as possible.

If your data may have been exposed

Because this vulnerability has been associated with ransomware use and can enable arbitrary file reads (especially when chained), successful exploitation may lead to data theft or further compromise. If you have evidence of exploitation or cannot rule it out, treat the incident as a potential breach: isolate affected systems, preserve logs, and follow your incident-response plan. Organizations can also run a free exposure scan of their email addresses against known breach data sets to determine whether credentials or personal information have already appeared in public dumps.