CVE-2018-14847
CVE-2018-14847 is a security flaw in MikroTik RouterOS, the operating system on MikroTik’s routers. Attackers can read files on MikroTik RouterOS that should be out of reach from anywhere, without logging in. The US Cybersecurity and Infrastructure Security Agency (CISA) added it to its catalog of flaws known to be used in attacks on 1 Dec 2021.[1]
MikroTik RouterOS 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. MikroTik has published a fix or advice.
Description
CISA calls it a router OS directory traversal in MikroTik RouterOS. In its words: “MikroTik RouterOS through 6.42 allows unauthenticated remote attackers to read arbitrary files and remote authenticated attackers to write arbitrary files due to a directory traversal vulnerability in the WinBox interface.”[1]
The underlying weakness is path traversal (CWE-22), in MITRE’s list of common software weaknesses.[2]
It scores 9.1 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; MikroTik’s advisory has them[3]. CISA names the product as MikroTik RouterOS.
Most families won’t have MikroTik RouterOS; it’s for whoever looks after IT at work.
Exploitation
CISA added it to its catalog of known exploited vulnerabilities on 1 Dec 2021, 1,217 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 1 Jun 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 96%. 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
MikroTik has published a fix or advice.[3] CISA’s required action: “Apply updates per vendor instructions.”[1]
- Check whether you use it.MikroTik RouterOS 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 1 Jun 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 9.1.[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 96%.[4] |
See also
Other MikroTik RouterOS flaws
- CVE-2026-67279: improper enforcement of behavioral workflow ·
- CVE-2026-86060: improper neutralization of argument delimiters in a command ·
- CVE-2026-67277: missing authentication for critical function ·
- CVE-2018-7445: stack-based buffer overflow ·
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-2021-44077, Zoho ManageEngine ServiceDesk Plus (SDP) / SupportCenter Plus: manageEngine serviceDesk plus remote code execution ·
- CVE-2021-40438, Apache: HTTP server-side request forgery (SSRF) ·
- CVE-2021-37415, Zoho ManageEngine ServiceDesk Plus (SDP): manageEngine serviceDesk authentication bypass ·
- CVE-2020-11261, Qualcomm Snapdragon Auto, Snapdragon Compute, Snapdragon Connectivity, Snapdragon Consumer IOT, Snapdragon Industrial IOT, Snapdragon Mobile, Snapdragon Voice & Music, Snapdragon Wearables: multiple chipsets improper input validation ·
Every MikroTik flaw on CISA’s list · Everything added in December 2021
References
- ^ Cybersecurity and Infrastructure Security Agency. “MikroTik Router OS Directory Traversal Vulnerability”. Known Exploited Vulnerabilities Catalog, added 1 Dec 2021.
- ^ National Institute of Standards and Technology. “CVE-2018-14847 Detail”. National Vulnerability Database, published 2 Aug 2018.
- ^ MikroTik. Advisories and fixes: mikrotik.com.
- ^ FIRST. “Exploit Prediction Scoring System”. EPSS 0.960, percentile 99.9, 31 Oct 2026.
- CVE Program. “CVE-2018-14847”. 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.