CVEs / CVE-2021-27104

CVE-2021-27104: Accellion FTA OS Command Injection Vulnerability

Known exploited in the CISA KEV catalog since 3 Nov 2021
critical 9.8 CVSS 3.1 (NVD)
EPSS 56.6% chance of exploitation in the next 30 days, higher than 99% of CVEs (30 Oct 2026)
Last changed at its sources 17 Jun 2026

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Summary

Accellion FTA contains an OS command injection vulnerability exploited via a crafted POST request to various admin endpoints.
CISA, Known Exploited Vulnerabilities catalog

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.
The CVE record, via NVD · published 16 Feb 2021 · NVD status: Analyzed

Affected and fixed versions

As stated by the CVE record (from the CNA)
Product	Affected	Fixed in
n/a n/a	n/a	—

Exploitation

In CISA KEV since	3 Nov 2021
Due date for US federal agencies	17 Nov 2021
Used in ransomware campaigns	Known
Required action	Apply updates per vendor instructions.

Severity

CVSS 3.1	9.8 critical `CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H` Scored by NVD
Weakness	CWE-78

References

CVE-2021-27104 on NVD
CVE-2021-27104 in the CISA KEV catalog
https://github.com/accellion/CVEs/blob/main/CVE-2021-27104.txt Broken Link, Third Party Advisory
https://www.accellion.com/products/fta/ Product, Vendor Advisory
https://www.cisa.gov/known-exploited-vulnerabilities-catalog?field_cve=CVE-2021-27104 US Government Resource

Sources

Exploitation status from the CISA Known Exploited Vulnerabilities catalog. EPSS scores from FIRST. Descriptions, severity and references from the National Vulnerability Database. Open-source package versions from OSV (CC-BY 4.0). Text is shown as each source states it; Stackurity does not edit it. Check the vendor's advisory before acting.

This product uses data from the NVD API but is not endorsed or certified by the NVD.