CVE-2019-8394
CVE-2019-8394 is a security flaw in Zoho ManageEngine, Zoho’s IT management software. Attackers can upload a file to Zoho ManageEngine and make it run. The US Cybersecurity and Infrastructure Security Agency (CISA) added it to its catalog of flaws known to be used in attacks on 3 Nov 2021.[1]
Zoho ManageEngine 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 a serviceDesk plus (SDP) file upload in Zoho ManageEngine. In its words: “Zoho ManageEngine ServiceDesk Plus (SDP) contains an unspecified vulnerability that allows remote users to upload files via login page customization.”[1]
The underlying weakness is unrestricted file upload (CWE-434), in MITRE’s list of common software weaknesses.[2]
It scores 6.5 out of 10 on the Common Vulnerability Scoring System, which rates it medium, 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 ManageEngine.
Most families won’t have Zoho ManageEngine; it’s for whoever looks after IT at work.
Exploitation
CISA added it to its catalog of known exploited vulnerabilities on 3 Nov 2021, 990 days after it was made public. CISA lists a flaw only when it has reliable evidence of it being exploited, and gave US federal agencies until 3 May 2022 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 63%. That’s in the top 1% of the flaws it scores.[4]
CISA assesses it as not automatable: each attack takes some work.
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 ManageEngine 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 3 May 2022 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 |
|---|---|
| The flaw is made public in the National Vulnerability Database, with a severity score of 6.5.[2] | |
| CISA adds it to its catalog of flaws known to be used in attacks.[1] | |
| 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 63%.[4] |
See also
Other Zoho ManageEngine flaws
- CVE-2022-28810: aDSelfService plus remote code execution ·
- CVE-2022-47966: multiple products remote code execution ·
- CVE-2022-35405: multiple products remote code execution ·
- CVE-2021-40539: aDSelfService plus authentication bypass ·
- CVE-2020-10189: desktop central file upload ·
Other Zoho flaws
- CVE-2021-44515, Zoho Desktop Central: authentication bypass ·
- 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 ·
Other unrestricted file upload flaws
- CVE-2026-48356, Adobe Commerce and Magento: unrestricted upload of file with dangerous type ·
- CVE-2026-56291, Balbooa Forms: unrestricted upload of file with dangerous type ·
- CVE-2026-48939, iCagenda: unrestricted upload of file with dangerous type ·
- CVE-2026-48908, JoomShaper SP Page Builder: unrestricted upload of file with dangerous type ·
- CVE-2024-7694, TeamT5 ThreatSonar Anti-Ransomware: unrestricted upload of file with dangerous type ·
Added the same day
- CVE-2021-42258, BQE BillQuick Web Suite: SQL injection ·
- CVE-2021-42013, Apache HTTP Server: path traversal ·
- CVE-2021-41773, Apache HTTP Server: path traversal ·
- CVE-2021-40539, Zoho ManageEngine: aDSelfService plus authentication bypass ·
- CVE-2021-40444, Microsoft MSHTML: remote code execution ·
Every Zoho flaw on CISA’s list · Everything added in November 2021
References
- ^ Cybersecurity and Infrastructure Security Agency. “Zoho ManageEngine ServiceDesk Plus (SDP) File Upload Vulnerability”. Known Exploited Vulnerabilities Catalog, added 3 Nov 2021.
- ^ National Institute of Standards and Technology. “CVE-2019-8394 Detail”. National Vulnerability Database, published 17 Feb 2019.
- ^ Zoho. Advisories and fixes: manageengine.com.
- ^ FIRST. “Exploit Prediction Scoring System”. EPSS 0.633, percentile 99.2, 31 Oct 2026.
- CVE Program. “CVE-2019-8394”. 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.