Actively exploited vulnerability

Fortinet FortiClient EMS: sql injection flaw under attack

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

Business software9.8 critical

What is affected

Fortinet FortiClient EMS is mostly run by companies, schools and public bodies, not on home computers. You are unlikely to have it yourself, but organisations that hold your data may. Breaches that start with flaws like this one are how personal data ends up leaked.

Fortinet FortiClient EMS contains a SQL injection vulnerability that may allow an unauthenticated attacker to execute unauthorized code or commands via specifically crafted HTTP requests.

CISA's description

What an attacker can do

This is a sql injection flaw. It lets an attacker read, change or delete records in the product's database. That often includes user accounts and stored passwords.

How it is reached
Over the internet or network
Access the attacker needs
No account needed
Does the victim have to do something?
No, works without the victim doing anything

What to do

  1. At home: nothing to install. Keep your own devices updated and use a different password for every service, so that a breach at one organisation does not open your other accounts.
  2. If you administer Fortinet FortiClient EMS at work: apply the vendor's fix or mitigation now and review logs for signs of compromise, because the flaw was being exploited before it was listed.
  3. If the product is past its support date and no fix exists, take it off the internet or retire it.

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

Action required by CISA for US federal agencies

Vendor advisories and fixes

How urgent is it

CISA added this vulnerability to its Known Exploited Vulnerabilities catalogue on April 13, 2026, which means there is reliable evidence of attacks in the wild. US federal agencies must fix it by April 16, 2026, a deadline that has already passed. That deadline does not bind anyone else, but it shows how seriously the agency rates it.

The EPSS model estimates a 94% probability that this flaw will be exploited somewhere in the next 30 days. That is higher than 99.8% of all scored vulnerabilities.

Its CVSS severity score is 9.8 out of 10 (critical), as recorded in the US National Vulnerability Database.

Technical 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.

NIST National Vulnerability Database
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