Threats / Fortinet / CVE-2026-21643
CVE-2026-21643
· EUVD no mirror located
· GCVE no mirror located
Verified 2026-08-04
Fortinet FortiClient EMS vulnerability
Fortinet FortiClient EMS contains a SQL injection vulnerability allowing unauthenticated attackers to execute unauthorized code via crafted HTTP requests.
Verdict
Today item — known-exploited.
SQL injection in FortiClient EMS enables remote code execution without authentication. Active exploitation observed in the wild with moderate exploit probability (EPSS 0.64). Immediate patching required for exposed instances.
CISA KEV Yes · 2026-04-135EPSS 0.94085 (verify live)6Exploit Public PoC7CVSS 9.13CISA SSVC Exploitation: active · Automatable: yes · Impact: total4
01
Is it exploitable?
— the evidence, ranked above the scoreExploit available
Public proof-of-concept exploit code is cataloged for this vulnerability.We link the existence of the exploit; we do not host or redistribute payloads.
Reported exploitation
105 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 2026-04-13).
Probability (EPSS)
EPSS 0.94085 — modeled likelihood of exploitation activity.EPSS is a daily-changing model output — open the source for today's value.
Severity / affected
CVSS 9.1 (CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H/E:F/RL:O/RC:C) · Affected: Fortinet, FortiClient EMS. Confirm exact fixed builds in the vendor advisory.CVSS — CNA-assigned (CVE.org), version 3.1, set at disclosure.
Weakness (CWE)
Mapped to CWE-89 SQL Injection — weakness family: Injection.CWE — CNA-assigned (CVE.org); the weakness class drives how the flaw is exploited.
CISA SSVC (triage disposition)
Exploitation: active · Automatable: yes · 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 66 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.
Public exploit available
Public exploit tooling is catalogued for this CVE (a public proof-of-concept / detection template). Catalog entries: nuclei template. We link the catalog page(s) only — no payload or code is hosted or restated here.Link, never host — the catalog page is the source; basicsecurity.net does not redistribute payloads.
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 malicious SQL payloads in HTTP requests to FortiClient EMS endpoints that lack input validation.
Business
Attackers gain unauthenticated database access, bypassing all authentication controls.
2
Keys to the kingdom — privilege/identity takeover narrative 2
Attacker
I execute arbitrary SQL commands to extract sensitive data or modify database records.
Business
Confidential endpoint management data, credentials, and configuration details are compromised.
3
Lateral reach — past segmentation narrative 3
Attacker
I escalate from SQL injection to remote code execution on the EMS server.
Business
Complete infrastructure compromise of the endpoint management system and connected client fleet.
4
Data at risk — exfiltration narrative 4
Attacker
I establish persistent access and lateral movement across managed endpoints.
Business
Enterprise-wide security posture degradation with potential for widespread malware distribution.
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