CVE-2026-21643: Fortinet FortiClient EMS SQL Injection Vulnerability

What it is

An improper neutralization of special elements used in an sql command (‘sql injection’) vulnerability in Fortinet FortiClientEMS 7.4.4 may allow an unauthenticated attacker to execute unauthorized code or commands via specifically crafted HTTP requests.

Description quoted from the CVE record (assigned by fortinet, published 2026-02-06).

Weakness: Execute unauthorized code or commands

How it can be exploited

Exploitable over the network with low attack complexity needing no privileges and no user interaction. Impact: confidentiality high, integrity high, availability high. 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

CISA assessment (SSVC): CISA assesses exploitation as active. Automatable: yes. Technical impact: total.

On CISA KEV since

2026-04-13

US federal deadline

2026-04-16

Ransomware use

Not known

Public exploit evidence (Exploit Observer)

Also known as: BDU:2026-01492, CNNVD-202602-1042, EUVD-2026-5681, GHSA-r6vr-hwpr-qqch

VEDAS cluster: VEDAS:DRAGONVOICE

Exploit Observer links 9 pieces of public exploit code or detection modules that name this CVE or one of its aliases.

Exploit code and modules (9)

Code that names this CVE. A repository can be a working exploit, a scanner, a fake or malware; read it before running anything.

• Nuclei template: https://raw.githubusercontent.com/projectdiscovery/nuclei-templates/main/http/cves/2026/CVE-2026-21643.yaml
• Code repository: https://github.com/0xblackash/cve-2026-21643
• Code repository: https://github.com/alirezac0/cve-2026-21643
• Code repository: https://github.com/darksploits/cve-2026-21643-exploit
• Code repository: https://raw.githubusercontent.com/ARPSyndicate/vedas-signatures/main/nuclei/2026/CVE-2026-21643.yaml
• Code repository: https://raw.githubusercontent.com/ARPSyndicate/vedas-signatures/main/nuclei/2026/CVE-2026-21643.yaml
• Code repository: https://raw.githubusercontent.com/ARPSyndicate/vedas-signatures/main/suricata/2026/CVE-2026-21643.rules
• Code repository: https://raw.githubusercontent.com/ARPSyndicate/vedas-signatures/main/suricata/2026/CVE-2026-21643.rules
• Code repository: https://raw.githubusercontent.com/ARPSyndicate/vedas-signatures/main/suricata/2026/CVE-2026-21643.rules

Research and write-ups (2)

• Research or write-up: https://bishopfox.com/blog/cve-2026-21643-pre-authentication-sql-injection-in-forticlient-ems-7-4-4
• Research or write-up: https://socprime.com/blog/cve-2026-21643-vulnerability

Vulnerability databases and vendor advisories (5)

Catalogue entries, not exploit evidence.

• Vulnerability database or vendor advisory: https://euvd.enisa.europa.eu/enisa/EUVD-2026-5681
• Vulnerability database or vendor advisory: https://github.com/advisories/GHSA-r6vr-hwpr-qqch
• Vulnerability database or vendor advisory: https://nvd.nist.gov/vuln/detail/CVE-2026-21643
• Vulnerability database or vendor advisory: https://www.cisa.gov/known-exploited-vulnerabilities-catalog?field_cve=CVE-2026-21643
• Vulnerability database or vendor advisory: https://www.cnnvd.org.cn/home/globalSearch?keyword=CNNVD-202602-1042

12 more references returned by Exploit Observer did not name this CVE or an alias, so they are left out.

VEDAS data as of 2026-11-01T17:12 UTC; fetched 2026-11-02.

Live scores

EPSS

0.977
very likely to be attacked soon

VEDAS

0.982
strong exploit evidence

On CISA KEV

Yes, since 2026-04-13

Detection rule

Nuclei · Suricata

Thin horizontal line: the “likely” (EPSS 0.10) or “strong” (VEDAS 0.90) threshold. Shaded “no data” areas are periods when cve-scores did not publish. The vertical line is the day CISA added it to its exploited list.

Who is affected

Version ranges exactly as the CVE record states them. “Before X” means X is the first fixed version.

Exploit Observer also maps it to: fortinet forticlientems, fortinet_inc. forticlientems.

How to fix it

CISA required action: Apply mitigations per vendor instructions, follow applicable BOD 22-01 guidance for cloud services, or discontinue use of the product if mitigations are unavailable.

Vendor guidance:

• https://fortiguard.fortinet.com/psirt/FG-IR-25-1142
• https://nvd.nist.gov/vuln/detail/CVE-2026-21643

How to detect it

Nuclei template (active check)

Fortinet FortiClientEMS - SQL Injection

An improper neutralization of special elements used in an sql command (‘sql injection’) vulnerability in Fortinet FortiClientEMS 7.4.4 may allow an unauthenticated attacker to execute unauthorized code or commands via specifically crafted HTTP requests.

Name and description quoted from the template, written by VEDAS.

The template sends 2 requests (GET /api/v1/init_consts, GET /api/v1/init_consts); it decides using dsl matchers. Severity in the template: critical. Marked as not yet verified against a live vulnerable target.

Run it against a host you own or are authorised to test:

nuclei -u https://your-host -t CVE-2026-21643.yaml

id: CVE-2026-21643

info:
  name: "Fortinet FortiClientEMS - SQL Injection"
  author: vedas-arpsyndicate
  severity: critical
  description: |
    An improper neutralization of special elements used in an sql command ('sql injection') vulnerability in
    Fortinet FortiClientEMS 7.4.4 may allow an unauthenticated attacker to execute unauthorized code or commands
    via specifically crafted HTTP requests.
  reference:
    - https://www.exploit.observer/?keyword=CVE-2026-21643&match=exact
    - https://subdomain.center/?engine=ammonites&keyword=forticlient&match=exact
  classification:
    cvss-metrics: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
    cvss-score: 9.8
    cve-id: CVE-2026-21643
    cwe-id: CWE-89
  metadata:
    verified: false
  tags: cve,cve2026,sqli,forticlient,ems,fortinet,vkev,kev
http:
  - raw:
      - |
        GET /api/v1/init_consts HTTP/1.1
        Host: {{Hostname}}

      - |
        @timeout: 20s
        GET /api/v1/init_consts HTTP/1.1
        Host: {{Hostname}}
        Site: tenant1; SELECT pg_sleep(8)--

    matchers-condition: and
    matchers:
      - type: dsl
        dsl:
          - 'contains(body_1, "SITES_ENABLED\": true")'

      - type: dsl
        name: time-based
        dsl:
          - "duration_2>=8"
          - "status_code_2 == 500"
        condition: and

CVE-2026-21643.yaml on GitHub

Suricata rules (network detection)

1 rule that alert on traffic matching this exploit: VEDAS CVE-2026-21643 Fortinet FortiClientEMS - SQL Injection. Add them to your Suricata rule set and reload.

alert http $EXTERNAL_NET any -> $HTTP_SERVERS $HTTP_PORTS (msg:"VEDAS CVE-2026-21643 Fortinet FortiClientEMS - SQL Injection"; flow:established,to_server; http.uri; content:"/api/v1/init_consts"; nocase; fast_pattern; classtype:web-application-attack; reference:cve,CVE-2026-21643; reference:url,https://www.exploit.observer/?keyword=CVE-2026-21643&match=exact; reference:url,https://subdomain.center/?engine=ammonites&keyword=forticlient&match=exact; sid:1010266; rev:1;)

CVE-2026-21643.rules on GitHub

References

Exploits and technical analysis

• https://github.com/0xBlackash/CVE-2026-21643/blob/main/cve-2026-21643.py (exploit)

Government sources

• https://www.cisa.gov/known-exploited-vulnerabilities-catalog?field_cve=CVE-2026-21643 (government-resource)

Other references

• https://fortiguard.fortinet.com/psirt/FG-IR-25-1142

Other databases

• CVE record (cve.org)
• NVD
• Exploit Observer

Where this comes from

This advisory is generated automatically by VEDAS from: CVE.org record, CISA KEV, cve-scores (EPSS and VEDAS), Exploit Observer, vedas-signatures. Text in quotes is reproduced from the source; everything else is a fixed template filled with source fields. Nothing here is written by a language model. Check the vendor advisory before acting, and read how VEDAS and Exploit Observer work, and their limits.