Threats / Accellion / CVE-2021-27102
CVE-2021-27102
· EUVD no mirror located
· GCVE no mirror located
Verified 2026-06-22
Accellion FTA vulnerability
Accellion FTA contains an OS command injection vulnerability in a local web service that has been exploited in the wild and leveraged in ransomware campaigns.
Verdict
Today item, not a backlog item.
A local web service in Accellion FTA accepts unsanitized input that can be exploited to execute arbitrary OS commands. Active exploitation and ransomware deployment have been documented, indicating significant real-world risk.
01
Is it exploitable?
— the evidence, ranked above the scoreReported exploitation
22 independent public reports of in-the-wild exploitation are cataloged.Distinct reporting sources (vendor, incident response, government); open them for the underlying claims.
Exploited in the wild
Listed in the CISA Known Exploited Vulnerabilities catalog (added 2021-11-03), flagged for known ransomware use.
Probability (EPSS)
EPSS 0.03654 — modeled likelihood of exploitation activity.EPSS is a daily-changing model output — open the source for today's value.
Severity / affected
Affected: Accellion, FTA. Confirm exact fixed builds in the vendor advisory.
Weakness (CWE)
Mapped to CWE-20 Improper Input Validation, CWE-78 OS Command Injection — weakness family: Injection.CWE assignment from the public NVD record; the weakness class drives how the flaw is exploited.
02
Who’s exploiting it?
— attribution turns risk into urgencyAttribution not established
No confirmed (advisory-backed) threat-actor attribution is established for this record. Absence of a named actor is not absence of compromise — see Coverage & confidence.
03
Why it matters
— the attack path, told twice: adversary, then board1
Front door — unauthenticated access narrative 1
Attacker
I craft a malicious request to the local web service with embedded OS commands.
Business
Unauthorized command execution on the FTA server enables full system compromise.
2
Keys to the kingdom — privilege/identity takeover narrative 2
Attacker
I escalate privileges and establish persistence on the compromised host.
Business
Attackers gain sustained access to sensitive file transfer infrastructure and stored data.
3
Lateral reach — past segmentation narrative 3
Attacker
I exfiltrate confidential files and deploy ransomware across the environment.
Business
Data breach and operational shutdown result in financial loss, regulatory exposure, and reputational damage.
04
What to do
— defensible action- Remediate per the vendor advisory — confirm the fixed build for your version and verify exposure.1
Say it to the boardA vulnerability with this evidence profile is a defensible budget line, not a backlog ticket — fund the change against the proof above.
05