CVE intelligence and bounded remediation

CVE-2020-12456 — Mitel Mivoice Connect Client security vulnerability

High CVSS 8.8

A remote code execution vulnerability in Mitel MiVoice Connect Client before 214.100.1223.0 could allow an attacker to execute arbitrary code in the chat notification window, due to improper rendering of chat messages. A successful exploit could allow an attacker to steal session cookies, perform directory traversal, and execute arbitrary scripts in the context of the Connect client.

Severity
High
CVSS
8.8 (3.1)
Published
2020-08-26
CISA KEV
Not currently listed
Ecosystem
software/application
Weaknesses
CWE-22

Affected products

  • mitel / mivoice_connect_client

Matched remediation archetype

Path traversal, unsafe upload, and file handling

This catalog composition supplies bounded fallback guidance. Explicitly reviewed curated workflows load with the complete record below.

Check exposure

  • Trace untrusted filenames, archive entries, URLs, and path segments into read, write, include, extraction, and upload operations.
  • Identify filesystem roots, mount permissions, symbolic-link behavior, archive handling, and whether uploaded content is web-accessible or executable.
  • Review canonicalization and containment checks across supported operating systems and storage backends.

Remediate safely

  • Generate server-side storage identifiers and resolve paths beneath a fixed root using filesystem-aware containment checks.
  • Reject absolute, parent-relative, alternate-separator, device, link, and archive entries that escape the intended root.
  • Store uploads outside executable or served paths, validate type and size, and use private atomic temporary files.

Authoritative sources

Complete CVE record and remediation plan

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