CVE-2019-18187
CVE-2019-18187 is a security flaw in Trend Micro OfficeScan, business antivirus software. Attackers can run their own code on Trend Micro OfficeScan. 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]
Trend Micro OfficeScan 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. Trend Micro has published a fix or advice.
Description
CISA calls it a directory traversal in Trend Micro OfficeScan. In its words: “Trend Micro OfficeScan contains a directory traversal vulnerability by extracting files from a zip file to a specific folder on the OfficeScan server, leading to remote code execution.”[1]
The CVE record adds: “Trend Micro OfficeScan versions 11.0 and XG (12.0) could be exploited by an attacker utilizing a directory traversal vulnerability to extract files from an arbitrary zip file to a specific folder on the OfficeScan server, which could potentially lead to remote code execution (RCE). The remote process execution is bound to a web service account, which depending on the web platform used may have restricted permissions. An attempted attack requires user authentication.”[2]
The underlying weakness is path traversal (CWE-22), in MITRE’s list of common software weaknesses.
It scores 7.5 out of 10 on the Common Vulnerability Scoring System, which rates it high, scored by NVD using CVSS 3.1.[2]
Affected versions
NVD’s record doesn’t list version ranges for it; Trend Micro’s advisory has them[3]. CISA names the product as Trend Micro OfficeScan.
Most families won’t have Trend Micro OfficeScan; it’s for whoever looks after IT at work.
Exploitation
CISA added it to its catalog of known exploited vulnerabilities on 3 Nov 2021, 737 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 25%. That’s in the top 3% 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
Trend Micro has published a fix or advice.[3] CISA’s required action: “Apply updates per vendor instructions.”[1]
- Check whether you use it.Trend Micro OfficeScan 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 7.5.[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 25%.[4] |
See also
Other Trend Micro flaws
- CVE-2026-34926, Trend Micro Apex One: (on-premise) directory traversal ·
- CVE-2025-54948, Trend Micro Apex One: OS command injection ·
- CVE-2023-41179, Trend Micro Apex One and Worry-Free Business Security: remote code execution ·
- CVE-2022-40139, Trend Micro Apex One and Apex One as a Service: improper validation ·
- CVE-2022-26871, Trend Micro Apex Central: arbitrary file upload ·
Other path traversal flaws
- CVE-2025-61624, Fortinet products: path traversal ·
- CVE-2021-3199, ONLYOFFICE Docs: server path traversal ·
- CVE-2026-104286, Fortinet FortiMail: path traversal ·
- CVE-2026-93616, Check Point products: path traversal ·
- CVE-2026-66384, JFrog Artifactory: improper limitation of a pathname to a restricted directory ·
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 Trend Micro flaw on CISA’s list · Everything added in November 2021
References
- ^ Cybersecurity and Infrastructure Security Agency. “Trend Micro OfficeScan Directory Traversal Vulnerability”. Known Exploited Vulnerabilities Catalog, added 3 Nov 2021.
- ^ National Institute of Standards and Technology. “CVE-2019-18187 Detail”. National Vulnerability Database, published 28 Oct 2019.
- ^ Trend Micro. Advisories and fixes: web.archive.org.
- ^ FIRST. “Exploit Prediction Scoring System”. EPSS 0.251, percentile 97.9, 31 Oct 2026.
- CVE Program. “CVE-2019-18187”. 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.