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Actively exploited

CVE-2021-44515 Zoho Desktop Central Authentication Bypass Vulnerability

Zoho Desktop Central contains an authentication bypass vulnerability that could allow an attacker to execute arbitrary code in the Desktop Central MSP server.

From the CISA KEV catalogue version 2026.11.06, with Cybergen analysis. Updated 6 Nov 2026.

Our Assessment

Should You Worry?

Patch nowCybergen assessment
  • CISA confirmed exploitation in the wild and added it to the Known Exploited Vulnerabilities catalogue on 10 Dec 2021.
  • Rated Critical severity (CVSS 9.8, scored by CISA).
  • It has been in the catalogue for 1,792 days. Systems still unpatched now have almost certainly been scanned for it.
The Vulnerability

What It Is

Zoho ManageEngine Desktop Central is vulnerable to authentication bypass, leading to remote code execution on the server, as exploited in the wild in December 2021. For Enterprise builds 10.1.2127.17 and earlier, upgrade to 10.1.2127.18. For Enterprise builds 10.1.2128.0 through 10.1.2137.2, upgrade to 10.1.2137.3. For MSP builds 10.1.2127.17 and earlier, upgrade to 10.1.2127.18. For MSP builds 10.1.2128.0 through 10.1.2137.2, upgrade to 10.1.2137.3.

From Watch to Action

What To Do Now

  1. 1

    Find it

    Search your asset inventory and external attack surface for Zoho Desktop Central. Include cloud images, appliances and anything a supplier runs for you.

    Attack Surface Management
  2. 2

    Fix it

    Apply updates per vendor instructions.

    Vulnerability Management
  3. 3

    Hunt for compromise

    If an affected system was reachable before you patched, assume it may have been hit. Check logs, new accounts, web shells and outbound connections from the date of exposure.

    Incident Response
  4. 4

    Prove it is fixed

    Rescan or test the system after patching. Upgrades that fail silently and forgotten secondary instances are common.

    Penetration Testing

Vendor Advisories

Regulation

The Compliance Clock

Cyber EssentialsRated critical, so if it affects devices in your Cyber Essentials scope, the update must be installed within 14 days of the vendor releasing it.NIS2If exploitation causes a significant incident, essential and important entities owe their CSIRT an early warning within 24 hours and a notification within 72 hours.DORAFinancial entities must classify ICT incidents and send an initial notification for a major incident within strict deadlines, with exploited flaws a common cause.US federal (BOD 22-01)Federal civilian agencies had until 24 Dec 2021 to remediate. A sensible benchmark for everyone else.

General guidance, not legal advice. Your obligations depend on your sector, scope and jurisdiction.

Stay Ahead

More Exploited Zoho Flaws

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CVE-2022-28810Zoho ManageEngine ADSelfService Plus Remote Code Execution VulnerabilityAdded 7 Mar 2023CVE-2022-47966 · RansomwareZoho ManageEngine Multiple Products Remote Code Execution VulnerabilityAdded 23 Jan 2023CVE-2022-35405Zoho ManageEngine Multiple Products Remote Code Execution VulnerabilityAdded 22 Sep 2022CVE-2021-37415Zoho ManageEngine ServiceDesk Authentication Bypass VulnerabilityAdded 1 Dec 2021CVE-2021-44077Zoho ManageEngine ServiceDesk Plus Remote Code Execution VulnerabilityAdded 1 Dec 2021CVE-2021-40539 · RansomwareZoho ManageEngine ADSelfService Plus Authentication Bypass VulnerabilityAdded 3 Nov 2021

All 9 exploited Zoho vulnerabilities

Not Sure If You Are Exposed?

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Evidence

Sources

  1. CISA Known Exploited Vulnerabilities catalogue
  2. NVD: CVE-2021-44515
  3. CVE record: CVE-2021-44515
  4. FIRST EPSS
  5. pitstop.manageengine.com/portal/en/community/topic/an-authentication-bypass-vulnerability-identified
  6. manageengine.com/products/desktop-central/cve-2021-44515-authentication-bypass-filter-configuration.
  7. cisa.gov/uscert/ncas/current-activity/2021/12/10/cisa-adds-thirteen-known-exploited-vulnerabilities-