What’s Vulnerable › Vulnerabilities

CVE-2022-29855

• Severity: medium (CVSS 6.8 v3.1)
• Exploited in the wild: not listed in CISA KEV
• EPSS: 0.8% probability of exploitation in the next 30 days
• Public exploit or detection template: yes
• Published: 2022-05-11 · updated 2026-06-17

Description

Mitel 6800 and 6900 Series SIP phone devices through 2022-04-27 have "undocumented functionality." A vulnerability in Mitel 6800 Series and 6900 Series SIP phones excluding 6970, versions 5.1 SP8 (5.1.0.8016) and earlier, and 6.0 (6.0.0.368) through 6.1 HF4 (6.1.0.165), could allow a unauthenticated attacker with physical access to the phone to gain root access due to insufficient access control for test functionality during system startup. A successful exploit could allow access to sensitive information and code execution.

Affected products

• Mitel 6865I Sip Firmware: before 5.1.0.8017; from 6.0.0.368 before 6.1.0.171 — fixed in 5.1.0.8017, 6.1.0.171
• Mitel 6867I Sip Firmware: before 5.1.0.8017; from 6.0.0.368 before 6.1.0.171 — fixed in 5.1.0.8017, 6.1.0.171
• Mitel 6869I Sip Firmware: before 5.1.0.8017; from 6.0.0.368 before 6.1.0.171 — fixed in 5.1.0.8017, 6.1.0.171
• Mitel 6873I Sip Firmware: before 5.1.0.8017; from 6.0.0.368 before 6.1.0.171 — fixed in 5.1.0.8017, 6.1.0.171
• Mitel 6905 Sip Firmware: through 5.1.0.8016; from 6.0.0.368 through 6.1.0.165
• Mitel 6910 Sip Firmware: through 5.1.0.8016; from 6.0.0.368 through 6.1.0.165
• Mitel 6920 Sip Firmware: through 5.1.0.8016; from 6.0.0.368 through 6.1.0.165
• Mitel 6930 Sip Firmware: before 5.1.0.8017; from 6.0.0.368 before 6.1.0.171 — fixed in 5.1.0.8017, 6.1.0.171
• Mitel 6940 Sip Firmware: before 5.1.0.8017; from 6.0.0.368 before 6.1.0.171 — fixed in 5.1.0.8017, 6.1.0.171

How to fix

Upgrade to a fixed version: Mitel 6865I Sip Firmware 5.1.0.8017, 6.1.0.171; Mitel 6867I Sip Firmware 5.1.0.8017, 6.1.0.171; Mitel 6869I Sip Firmware 5.1.0.8017, 6.1.0.171; Mitel 6873I Sip Firmware 5.1.0.8017, 6.1.0.171; Mitel 6930 Sip Firmware 5.1.0.8017, 6.1.0.171; Mitel 6940 Sip Firmware 5.1.0.8017, 6.1.0.171. Check the vendor advisory for mitigations.

References

• http://packetstormsecurity.com/files/167547/Mitel-6800-6900-Series-SIP-Phones-Backdoor-Access.html
• http://seclists.org/fulldisclosure/2022/Jun/32
• https://www.mitel.com/support/security-advisories
• https://www.mitel.com/support/security-advisories/mitel-product-security-advisory-22-0004
• https://www.syss.de/pentest-blog/undocumented-functionality-backdoor-in-mitel-desk-phones-syss-2022-021
• http://packetstormsecurity.com/files/167547/Mitel-6800-6900-Series-SIP-Phones-Backdoor-Access.html
• http://seclists.org/fulldisclosure/2022/Jun/32
• https://www.mitel.com/support/security-advisories
• https://www.mitel.com/support/security-advisories/mitel-product-security-advisory-22-0004
• https://www.syss.de/pentest-blog/undocumented-functionality-backdoor-in-mitel-desk-phones-syss-2022-021

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