Is CVE-2021-27104 in the CISA KEV catalog?

Yes. CVE-2021-27104 is on the CISA Known Exploited Vulnerabilities list, added 2021-11-03, and has known ransomware campaign use.

What is the CVSS severity of CVE-2021-27104?

CVE-2021-27104 has a CVSS v3 base score of 9.8 (CRITICAL).

What is the EPSS score for CVE-2021-27104?

CVE-2021-27104 has an EPSS score of 56.69% (99th percentile), estimating the probability of exploitation in the next 30 days.

CVE & CISA-KEV Catalog

CVE-2021-27104

CRITICALCISA KEVEPSS 99th pctl

9.8

CVSS v3

NVD

Description

Accellion FTA 9_12_370 and earlier is affected by OS command execution via a crafted POST request to various admin endpoints. The fixed version is FTA_9_12_380 and later.

CWE-78OS Command Injection

CVSS v3 Vector

Exploitability

Attack VectorNetwork

Attack ComplexityLow

Privileges RequiredNone

User InteractionNone

ScopeUnchanged

Impact

ConfidentialityHigh

IntegrityHigh

AvailabilityHigh

CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H

Exploit Intelligence

56.69%probability of exploitation in 30 days

99thpercentile

Very high risk: more likely to be exploited than 99% of all known CVEs.

Known Exploited Vulnerability (CISA KEV)

Accellion FTA OS Command Injection Vulnerability

Accellion FTA contains an OS command injection vulnerability exploited via a crafted POST request to various admin endpoints.

Apply updates per vendor instructions.

Remediation due: 2021-11-17

Associated with ransomware campaigns

References

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This product uses NVD data but is not endorsed or certified by the NVD. EPSS scores courtesy of FIRST.org (https://www.first.org/epss). Source: CISA KEV Catalog. Data as of 2025-11-03.