What is CVE-2022-26143?

CVE-2022-26143 is a critical-severity vulnerability in Mitel Micollab, classified under Missing Authentication for Critical Function. CVSS score: 9.8/10. Published 2022-03-10.

How severe is CVE-2022-26143?

Critical severity. CVSS v3 base score is 9.8 out of 10.

Is CVE-2022-26143 known to be exploited?

Yes. CVE-2022-26143 is listed in the CISA Known Exploited Vulnerabilities catalog (added 2022-03-25), indicating it is being actively exploited. 6 public proof-of-concept repositories are indexed.

Auth bypass in Mitel Micollab

CVE-2022-26143

The TP-240 (aka tp240dvr) component in Mitel MiCollab before 9.4 SP1 FP1 and MiVoice Business Express through 8.1 allows remote attackers to obtain sensitive information and cause a denial of service (performance degradation and excessive outbound traffic). This was exploited in the wild in February and March 2022 for the TP240PhoneHome DDoS attack.

Vulnerability class: Broken Authentication

Published 2022-03-10 · last modified 2026-06-17.

CVSS v3 metric

CVSS v3 base score 9.8 (Critical). Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H.

EPSS exploit prediction

EPSS: 0.873 (99.8th percentile), scored 2026-10-17.

High probability of exploitation in the next 30 days — patch promptly. 100th percentile — 99.8% of CVEs in the catalogue have a lower EPSS than this one. How to read EPSS.

EPSS over last 30 days · oldest: 0.873 · newest: 0.873 · change: 0.000

Affected products

Mitel Micollab — versions 9.4
Mitel Mivoice Business Express

Weakness classification (CWE)

CWE-306 — Missing Authentication for Critical Function

CISA KEV (Known Exploited Vulnerabilities)

This CVE is on the CISA KEV catalog, added on 2022-03-25. CISA KEV inclusion means CISA has confirmed in-the-wild exploitation; US federal agencies are required to remediate within a published due date.

BOD 22-01 due date: 2022-04-15.

Required action: Apply updates per vendor instructions.

Public proof-of-concept exploits

References

www.mitel.com/en-ca/support/security-advisories/mitel-product-security-advisory… (Vendor Advisory)
www.akamai.com/blog/security/phone-home-ddos-attack-vector (Third Party Advisory, Mitigation)
www.shadowserver.org/news/cve-2022-26143-tp240phonehome-reflection-amplificatio… (Third Party Advisory, Mitigation)
news.ycombinator.com/item (Third Party Advisory, Issue Tracking)
blog.cloudflare.com/cve-2022-26143/ (Third Party Advisory, Mitigation)
team-cymru.com/blog/2022/03/08/record-breaking-ddos-potential-discovered-cve-20… (Third Party Advisory, Mitigation, Broken Link)
arstechnica.com/information-technology/2022/03/ddosers-use-new-method-capable-o… (Exploit, Third Party Advisory, Press/Media Coverage)
134c704f-9b21-4f2e-91b3-4a467353bcc0 (US Government Resource)

Frequently asked questions

What is CVE-2022-26143?: CVE-2022-26143 is a critical-severity vulnerability in Mitel Micollab, classified under Missing Authentication for Critical Function. CVSS score: 9.8/10. Published 2022-03-10.
How severe is CVE-2022-26143?: Critical severity. CVSS v3 base score is 9.8 out of 10.
Is CVE-2022-26143 known to be exploited?: Yes. CVE-2022-26143 is listed in the CISA Known Exploited Vulnerabilities catalog (added 2022-03-25), indicating it is being actively exploited. 6 public proof-of-concept repositories are indexed.