Threats / Accellion / CVE-2021-27101
CVE-2021-27101
· EUVD no mirror located
· GCVE no mirror located
Verified 2026-08-04
Accellion FTA vulnerability
Accellion FTA contains a SQL injection vulnerability in document_root.html exploitable via crafted host headers. The vulnerability has been exploited in the wild and leveraged in ransomware campaigns.
Verdict
Today item, not a backlog item.
SQL injection in Accellion FTA allows unauthenticated attackers to inject malicious SQL through HTTP host headers, enabling unauthorized data access and modification. Active exploitation and ransomware deployment confirm high-severity real-world impact.
CISA KEV Yes · 2021-11-034Ransomware use Flagged4EPSS 0.05949 (verify live)5CVSS 9.8 (CISA)3CISA SSVC Exploitation: active · Automatable: no · Impact: total3
01
Is it exploitable?
— the evidence, ranked above the scoreReported exploitation
25 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 0.05949 — modeled likelihood of exploitation activity.EPSS is a daily-changing model output — open the source for today's value.
Severity / affected
CVSS 9.8 (CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H) · Affected: Accellion, FTA. Confirm exact fixed builds in the vendor advisory.CVSS — CISA-assigned via the ADP container (CVE.org), version 3.1; the CNA left no metrics, so CISA's own score is used ahead of NVD.
Weakness (CWE)
Mapped to CWE-89 SQL Injection, CWE-138 CWE-138 — weakness family: Injection.CWE assignment from the public NVD record (may be stale); the weakness class drives how the flaw is exploited.
CISA SSVC (triage disposition)
Exploitation: active · Automatable: no · Technical Impact: totalCISA's own stakeholder-specific triage inputs, published in the CVE record (CISA Coordinator role). NOTE: this is CISA's three decision points; the final Act/Attend/Track decision also requires a Mission & Well-being input not published here, so no overall decision is asserted.
Currency of the record
CISA added this to its KEV catalog 260 days after the CVE record was published.KEV lag = CISA-KEV dateAdded − CVE.org datePublished; a floor on how long the known-exploited flaw sat in the public record before the federal catalog listed it. Severity/weakness here is CNA- or CISA-assigned (current at disclosure), independent of NVD's analysis backlog.
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 host header containing SQL syntax and send it to the document_root.html endpoint.
Business
Attackers gain unauthorized access to sensitive file transfer data stored in the FTA database.
2
Keys to the kingdom — privilege/identity takeover narrative 2
Attacker
I execute database queries to extract customer files, credentials, and metadata from the compromised system.
Business
Customer data and intellectual property are exfiltrated, creating breach notification and regulatory compliance obligations.
3
Lateral reach — past segmentation narrative 3
Attacker
I establish persistent access by modifying database records or deploying web shells on the FTA server.
Business
Attackers maintain long-term presence for ransomware deployment or continued data theft operations.
4
Data at risk — exfiltration narrative 4
Attacker
I encrypt files on the compromised FTA infrastructure and demand ransom for decryption keys.
Business
Business operations halt; customers lose access to critical file transfer services and face extortion demands.
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