CVE-2026-106173: Fortinet FortiSIEM advisory

Advisory generated from the CVE record, CISA, Exploit Observer and VEDAS: what it is, whether it is exploited, who is affected, and how to fix and detect it.

What it is

A improper limitation of a pathname to a restricted directory (‘path traversal’) vulnerability in Fortinet FortiSIEM 7.5.0 may allow attacker to execute unauthorized code or commands via specially crafted packets.

Description quoted from the CVE record (assigned by fortinet, published 2026-10-13).

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:H/RL:O/RC:C

CISA assessment (SSVC): CISA assesses that a public proof of concept exists. Automatable: yes. Technical impact: total.

Public exploit evidence (Exploit Observer)

Exploit Observer found 9 code repositories and 1 research write-up naming this CVE.

Horizon3.ai analysis

Code repositories that name a CVE are often scanners, copies or fakes, and some are malware. Read the code before running anything.

See all 13 references on Exploit Observer

Live scores

EPSS: 0.010
low predicted chance of attack
VEDAS: 0.986
strong exploit evidence
On CISA KEV: Not listed
Detection rule: Nuclei · Suricata

Who is affected

Product	Affected	Not affected
Fortinet FortiSIEM	version 7.5.0 from 7.4.0 up to and including 7.4.2 from 7.3.0 up to and including 7.3.5 from 7.2.0 up to and including 7.2.7 from 7.1.0 up to and including 7.1.9 from 7.0.0 up to and including 7.0.4	Not stated

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

How to fix it

No fixed version or vendor advisory is listed in the CVE record yet. Watch the vendor’s security page.

How to detect it

Nuclei template (active check)

Fortinet FortiSIEM - Path Traversal
Fortinet FortiSIEM 7.5.0 exposes an unauthenticated gRPC service (phoenixSvc.SendQueryResult) over TLS on tcp/27918. The RPC concatenates the attacker-controlled “query-id” metadata into a filesystem path without validation, allowing path traversal and arbitrary file write that leads to remote code execution (CWE-22). This template is a non-destructive exposure check: it performs the HTTP/2 client preface handshake over TLS and confirms a live HTTP/2 (gRPC) server on the FortiSIEM phoenixSvc port, without sending any traversal payload or writing any file.

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

The template decides using word 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:

bash

nuclei -u https://your-host -t CVE-2026-106173.yaml

Show the template (43 lines)

yaml

id: CVE-2026-106173

info:
  name: "Fortinet FortiSIEM - Path Traversal"
  author: vedas-arpsyndicate
  severity: critical
  description: |
    Fortinet FortiSIEM 7.5.0 exposes an unauthenticated gRPC service (phoenixSvc.SendQueryResult) over
    TLS on tcp/27918. The RPC concatenates the attacker-controlled "query-id" metadata into a filesystem
    path without validation, allowing path traversal and arbitrary file write that leads to remote code
    execution (CWE-22). This template is a non-destructive exposure check: it performs the HTTP/2 client
    preface handshake over TLS and confirms a live HTTP/2 (gRPC) server on the FortiSIEM phoenixSvc port,
    without sending any traversal payload or writing any file.
  reference:
    - https://www.exploit.observer/?keyword=CVE-2026-106173&match=exact
    - https://subdomain.center/?engine=ammonites&keyword=fortisiem&match=exact
  classification:
    cvss-metrics: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
    cve-id: CVE-2026-106173
    cwe-id: CWE-22
  metadata:
    verified: false
  tags: cve,cve2026,fortinet,fortisiem,grpc,traversal,lfi,rce,network,tcp

tcp:
  - inputs:
      # HTTP/2 client connection preface ("PRI * HTTP/2.0\r\n\r\nSM\r\n\r\n")
      # followed by the mandatory empty SETTINGS frame. No gRPC request, no
      # path-traversal metadata and no file write are sent.
      - data: "\x50\x52\x49\x20\x2a\x20\x48\x54\x54\x50\x2f\x32\x2e\x30\x0d\x0a\x0d\x0a\x53\x4d\x0d\x0a\x0d\x0a\x00\x00\x00\x04\x00\x00\x00\x00\x00"

    host:
      - "tls://{{Hostname}}"
    port: 27918
    read-size: 1024

    matchers:
      # A compliant HTTP/2 (gRPC) server answers the preface with its own
      # SETTINGS frame: type 0x04, flags 0x00 (not ACK), stream id 0x00000000.
      - type: word
        part: raw
        words:
          - "\x04\x00\x00\x00\x00\x00"

CVE-2026-106173.yaml on GitHub

Suricata rules (network detection)

1 rule that alert on traffic matching this exploit: VEDAS CVE-2026-106173 FortiSIEM - gRPC phoenixSvc Path Traversal RCE Connection Attempt on tcp/27918. Add them to your Suricata rule set and reload.

Show the rules

suricata

alert tcp $EXTERNAL_NET any -> $HOME_NET 27918 (msg:"VEDAS CVE-2026-106173 FortiSIEM - gRPC phoenixSvc Path Traversal RCE Connection Attempt on tcp/27918"; flow:established,to_server; content:"|16 03|"; depth:2; classtype:attempted-admin; reference:cve,CVE-2026-106173; reference:url,https://www.exploit.observer/?keyword=CVE-2026-106173&match=exact; reference:url,https://subdomain.center/?engine=ammonites&keyword=fortisiem&match=exact; sid:1078201; rev:1;)

CVE-2026-106173.rules on GitHub

References

Exploit code

https://github.com/horizon3ai/CVE-2026-106173 (exploit)

Other references

https://fortiguard.fortinet.com/psirt/FG-IR-26-180

Other databases

Where this comes from

This advisory is generated automatically by VEDAS from: CVE.org record, 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.