CVE-2021-27221

HIGHNVD 8.18.1—Elevated

8.1

MikroTik RouterOS 6.47.9 allows remote authenticated ftp users to create or overwrite arbitrary .rsc files via the /export command. NOTE: the vendor's position is that this is intended behavior because of how user policies work

CVSS v3: 8.1
EG Score: 8.1(medium)
EPSS: 97.5%
KEV: Not listed

Published

March 19, 2021

Last Modified

November 21, 2024

References (2)

cve@mitrehttps://onovy.medium.com/routeros-user-with-just-ftp-policy-can-write-to-filesystem-cve-2021-27221-e3e45d780dfe
af854a3a-2127-422b-91ae-364da2661108https://onovy.medium.com/routeros-user-with-just-ftp-policy-can-write-to-filesystem-cve-2021-27221-e3e45d780dfe

Weakness Classification(1)

MITRE Common Weakness Enumeration — the root-cause categories this CVE belongs to.

CWE-77Command Injection

Data Freshness Timeline

(refreshed 9× in last 7d / 15× in last 30d)

Every time one of our enrichment pipelines (NVD, MITRE cvelistV5, EPSS, CISA KEV, GHSA, OSV, vendor advisories) ran against this CVE. Most recent first.

2026-06-04 13:10 UTCepss_batch
2026-06-04 13:10 UTCepss_batch
2026-06-02 20:11 UTCepss_batch
2026-06-02 20:11 UTCepss_batch
2026-06-02 20:11 UTCepss_batch
2026-05-31 22:29 UTCepss_batch
2026-05-31 22:29 UTCepss_batch
2026-05-31 00:15 UTCepss_batch
2026-05-29 13:42 UTCepss_batch
2026-05-28 13:43 UTCepss_batch
2026-05-28 13:43 UTCepss_batch
2026-05-26 19:37 UTCEG score recompute
2026-05-26 19:37 UTCGHSA enrichment
2026-05-26 07:17 UTCepss_batch
2026-05-26 07:17 UTCepss_batch

Frequently asked(5)

What is CVE-2021-27221?

CVE-2021-27221 is a high vulnerability published on March 19, 2021. MikroTik RouterOS 6.47.9 allows remote authenticated ftp users to create or overwrite arbitrary .rsc files via the /export command. NOTE: the vendor's position is that this is intended behavior because of how user policies work

When was CVE-2021-27221 disclosed?

CVE-2021-27221 was first published in the National Vulnerability Database on March 19, 2021, with the most recent update on November 21, 2024. EchelonGraph re-ingests CVE updates from NVD on a 2-hour cycle, so this page reflects the latest published state.

Is CVE-2021-27221 actively exploited?

CVE-2021-27221 is not currently on CISA's Known Exploited Vulnerabilities catalog. FIRST EPSS estimates a 97.5% percentile likelihood of exploitation in the next 30 days — higher percentiles indicate greater predicted risk.

What is the CVSS score of CVE-2021-27221?

CVE-2021-27221 has a CVSS v3 base score of 8.1 (NVD).

How do I remediate CVE-2021-27221?

Patch to the fixed version published by the affected vendor. Where vendor advisories exist for CVE-2021-27221, EchelonGraph cross-links them in the Vendor Advisories panel below — those typically contain the canonical remediation steps, fixed version numbers, and any vendor-specific mitigations.

Dependency Blast Radius

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CVE-2021-27221

📅 Published

🔄 Last Modified

🔗 References (2)

Weakness Classification(1)

Data Freshness Timeline

❓ Frequently asked(5)

Dependency Blast Radius

Is Your Infrastructure Affected by CVE-2021-27221?

🔗 Related CVEs(same CWE)

Same CWE

Published

Last Modified

References (2)

Frequently asked(5)

Related CVEs(same CWE)