CVE-2023-36553: Fortinet FortiSIEM · Execute unauthorized code or commands
Affects Fortinet FortiSIEMSource CVE Database V5
Not known to be exploited · CVSS 9.3 Critical.
Data as of 25 Oct 2026, 19:02 UTC
- EPSS
- 1.8% chance of exploitation in 30 days – higher than 79% of CVEsExploit Prediction Scoring System: the likelihood attackers will use this flaw soon.
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H/E:P/RL:X/RC:XExploitation evidence
Disclosed: evidence found.
CVE published 14 Nov 2023
Detectable: no evidence on record.
No public nuclei template indexed
Weaponised: no evidence on record.
No public exploit code indexed in Metasploit or Exploit-DB
Exploited in the wildExploited: no evidence on record.
Not in CISA KEV and no source reports exploitation
Observed by OffSeq MirageSeen by Mirage: no evidence on record.
No attack traffic recorded by OffSeq Mirage sensors
A missing step is not evidence of safety. Sources: cve.org (opens in a new tab), the Metasploit, Exploit-DB and nuclei-templates index as of 2026-10-25.
What to do
Affected software
| Product | Affected | Fixed in |
|---|---|---|
| Fortinet FortiSIEM | Affected
| Fixed in– |
AI-suggested
Given the absence of official patches in the provided information, European organizations should immediately implement the following mitigations: 1) Restrict API access to FortiSIEM systems by enforcing strict network segmentation and firewall rules, allowing only trusted management networks to communicate with the API endpoints. 2) Implement strong access controls and monitoring on FortiSIEM management interfaces to detect and block suspicious API requests. 3) Employ Web Application Firewalls (WAFs) or Intrusion Prevention Systems (IPS) with rules targeting OS command injection patterns to filter malicious traffic. 4) Regularly audit and monitor FortiSIEM logs for anomalies indicative of exploitation attempts. 5) Coordinate with Fortinet support to obtain and apply any available patches or hotfixes as soon as they are released. 6) Consider deploying compensating controls such as multi-factor authentication on management interfaces and isolating FortiSIEM from internet-facing networks. 7) Conduct internal penetration testing to validate the effectiveness of mitigations and identify any residual risks. These steps will reduce the attack surface and limit the potential for exploitation until a vendor patch is available.
Description
CVE-2023-36553 is a critical OS command injection vulnerability in multiple versions of Fortinet FortiSIEM, allowing unauthenticated attackers to execute arbitrary code or commands via crafted API requests. The flaw arises from improper neutralization of special elements in OS commands, affecting versions from 4.7.2 through 5.4.0. Exploitation requires no authentication or user interaction and can lead to full system compromise, impacting confidentiality, integrity, and availability. No known exploits are currently reported in the wild, but the high CVSS score (9.3) indicates a severe risk. European organizations using FortiSIEM for security information and event management are at risk, especially in countries with high Fortinet market penetration and critical infrastructure reliance.