CVE-2021-44515
CVE-2021-44515 is a security flaw in Zoho Desktop Central. Attackers can run their own code on Zoho Desktop Central. The US Cybersecurity and Infrastructure Security Agency (CISA) added it to its catalog of flaws known to be used in attacks on 10 Dec 2021.[1]
Zoho Desktop Central is business software or equipment. Most families won’t have it, but attackers break into it to get inside companies, and from there to what those companies hold about their customers, patients and staff. Zoho has published a fix or advice.
Description
CISA calls it an authentication bypass in Zoho Desktop Central. In its words: “Zoho Desktop Central contains an authentication bypass vulnerability that could allow an attacker to execute arbitrary code in the Desktop Central MSP server.”[1]
The CVE record adds: “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.”[2]
It scores 9.8 out of 10 on the Common Vulnerability Scoring System, which rates it critical, scored by NVD using CVSS 3.1.[2]
Affected versions
NVD’s record doesn’t list version ranges for it; Zoho’s advisory has them[3]. CISA names the product as Zoho Desktop Central.
Most families won’t have Zoho Desktop Central; it’s for whoever looks after IT at work.
Exploitation
CISA added it to its catalog of known exploited vulnerabilities on 10 Dec 2021. CISA lists a flaw only when it has reliable evidence of it being exploited, and gave US federal agencies until 24 Dec 2021 to fix it.[1]
FIRST’s Exploit Prediction Scoring System, which estimates how likely a flaw is to be used in attacks in the next 30 days from what it sees across the internet, puts it at over 99%. That’s in the top 1% of the flaws it scores.[4]
CISA assesses it as automatable: attackers can run it against many targets at once.
CISA doesn’t say who was attacked, or how.
Fix
Zoho has published a fix or advice.[3] CISA’s required action: “Apply updates per vendor instructions.”[1]
- Check whether you use it.Zoho Desktop Central is business software or equipment, so most families won’t have it. If you run a business, or work from home on company equipment, ask whoever looks after your IT.
- Send this page to your IT person.Ask them to confirm it’s fixed, or not in use. CISA gave US government agencies until 24 Dec 2021 to fix it.
- If it can’t be fixed, take it offline.CISA’s advice when there’s no fix is to stop using the product, or take it off the internet, until there is one.
You can’t fix someone else’s server, but you can watch for what follows a break-in like this: a breach notice, a password reset you didn’t ask for, or a scam message that knows things it shouldn’t. HARD watches for those for you and your family.
Timeline
| Date | Event |
|---|---|
| CISA adds it to its catalog of flaws known to be used in attacks.[1] | |
| The flaw is made public in the National Vulnerability Database, with a severity score of 9.8.[2] | |
| CISA’s deadline for US government agencies to fix it.[1] | |
| FIRST puts the odds of it being used in attacks in the next 30 days at over 99%.[4] |
See also
Other Zoho flaws
- CVE-2022-28810, Zoho ManageEngine: aDSelfService plus remote code execution ·
- CVE-2022-47966, Zoho ManageEngine: multiple products remote code execution ·
- CVE-2022-35405, Zoho ManageEngine: multiple products remote code execution ·
- CVE-2021-44077, Zoho ManageEngine ServiceDesk Plus (SDP) / SupportCenter Plus: manageEngine serviceDesk plus remote code execution ·
- CVE-2021-37415, Zoho ManageEngine ServiceDesk Plus (SDP): manageEngine serviceDesk authentication bypass ·
Similar flaws
- CVE-2026-111357, Ivanti Connect Secure: missing authentication for critical function ·
- CVE-2026-97229, GitLab Community Edition and Enterprise Edition: integer overflow or wraparound ·
- CVE-2026-76418, Cisco Secure Firewall ASA Software and Cisco Secure FTD Software: unchecked return value to NULL pointer dereference ·
- CVE-2026-48356, Adobe Commerce and Magento: unrestricted upload of file with dangerous type ·
- CVE-2026-111497, Google Brotli: unchecked return value ·
Added the same day
- CVE-2021-44228, Apache Log4j2: remote code execution ·
- CVE-2021-44168, Fortinet FortiOS: arbitrary file download ·
- CVE-2021-35394, Realtek Jungle Software Development Kit (SDK): jungle SDK remote code execution ·
- CVE-2020-8816, Pi-hole AdminLTE: remote code execution ·
- CVE-2020-17463, Fuel CMS: SQL injection ·
Every Zoho flaw on CISA’s list · Everything added in December 2021
References
- ^ Cybersecurity and Infrastructure Security Agency. “Zoho Desktop Central Authentication Bypass Vulnerability”. Known Exploited Vulnerabilities Catalog, added 10 Dec 2021.
- ^ National Institute of Standards and Technology. “CVE-2021-44515 Detail”. National Vulnerability Database, published 12 Dec 2021.
- ^ Zoho. Advisories and fixes: pitstop.manageengine.com.
- ^ FIRST. “Exploit Prediction Scoring System”. EPSS 0.999, percentile 100.0, 31 Oct 2026.
- CVE Program. “CVE-2021-44515”. The official CVE record.
This article is built from CISA’s catalog (version 2026.10.30), NVD’s record and FIRST’s scores, kept in HARD’s database and checked every morning. The plain English is HARD’s.