Threats / Accellion / CVE-2021-27103
CVE-2021-27103
· EUVD no mirror located
· GCVE no mirror located
Verified 2026-08-04
Accellion FTA vulnerability
Accellion FTA contains a server-side request forgery vulnerability in wmProgressstat.html exploited via crafted POST requests. The flaw has been weaponized in ransomware campaigns.
Verdict
Today item, not a backlog item.
SSRF in Accellion FTA enables attackers to forge requests from the server to internal or external systems, facilitating reconnaissance, lateral movement, and data exfiltration. Active exploitation in ransomware operations confirms real-world threat.
CISA KEV Yes · 2021-11-034Ransomware use Flagged4EPSS 0.11315 (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
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 0.11315 — 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-918 Server-Side Request Forgery (SSRF).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 POST request to wmProgressstat.html that causes the FTA server to make requests to internal systems or external targets on my behalf.
Business
Attackers gain unauthorized access to internal network resources and sensitive data, leading to compromise of confidential information and operational disruption.
2
Keys to the kingdom — privilege/identity takeover narrative 2
Attacker
I use the SSRF to probe internal network topology, enumerate services, and identify additional targets for lateral movement within the victim environment.
Business
The organization faces expanded attack surface as internal systems become exposed to compromise, increasing risk of widespread infrastructure takeover.
3
Lateral reach — past segmentation narrative 3
Attacker
I leverage the compromised FTA server as a pivot point to deploy ransomware payloads across the network, encrypting critical business data.
Business
Operations halt as ransomware spreads through the network, resulting in data loss, extortion demands, regulatory penalties, and severe 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