CVE-2021-27104
KEVRansomware UseAccellion FTA OS Command Injection Vulnerability
Description
Accellion FTA contains an OS command injection vulnerability exploited via a crafted POST request to various admin endpoints.
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.
CVSS 3.1 vector
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:HPublishedFeb 16, 2021
Last modifiedJun 17, 2026
Added to KEVNov 3, 2021
Remediation dueNov 17, 2021
References
- github.com/accellion/CVEs/blob/main/CVE-2021-27104.txtBroken LinkThird Party Advisory
- accellion.com/products/fta/ProductVendor Advisory
- cisa.gov/known-exploited-vulnerabilities-catalog?field_cve=CVE-2021-27104US Government Resource
0 recent articles mention this CVE
95
Risk assessment · Critical
Actively exploited and used by ransomware crews. Patch immediately.
- Exploitation
- Confirmed in the wild (CISA KEV)
- Federal remediation deadline
- Overdue by 1805 days
- Ransomware
- Used in known ransomware campaigns
- CVSS
- 9.8 CRITICAL
- EPSS (30-day exploit probability)
- 56.7% · top 1% of all CVEs
- Weakness
- CWE-78
- Attack vector
- Network, remotely reachable
- Preconditions
- No privileges and no user interaction
Recommended actions
- 1.Apply updates per vendor instructions.
- 2.Treat as emergency change: patch or isolate internet-facing instances first.
- 3.Review exposure: confirm which instances are reachable from the internet and restrict access until patched.
- 4.Hunt for compromise: review logs for the disclosure window, not just from the patch date.
- 5.Verify offline/immutable backups and segment the affected systems. This flaw is used for ransomware initial access.
Assessment is derived automatically from the live signals above; verify against your own asset inventory.