cbcvebase.
CVE-2026-25089
published 2026-06-09

CVE-2026-25089: A improper neutralization of special elements used in an os command ('os command injection') vulnerability in Fortinet FortiSandbox 5.0.0 through 5.0.5…

PriorityP1100critical9.8CVSS 3.1
AVNACLPRNUINSUCHIHAH
KEVITW
CISA Known Exploited Vulnerabilitydue 2026-07-19
Exploited in the wild
EPSS
76.11%
99.5th percentile
A improper neutralization of special elements used in an os command ('os command injection') vulnerability in Fortinet FortiSandbox 5.0.0 through 5.0.5, FortiSandbox 4.4.0 through 4.4.8, FortiSandbox 4.2 all versions, FortiSandbox Cloud 5.0.4 through 5.0.5, FortiSandbox PaaS 5.0.4 through 5.0.5 may allow an unauthenticated attacker to execute unauthorized commands via specifically crafted HTTP requests

Affected

12 ranges
VendorProductVersion rangeFixed in
fortinetfortinet
fortinetfortisandbox
fortinetfortisandbox4.2.0 – 4.2.8
fortinetfortisandbox4.2.1 – 4.2.8
fortinetfortisandbox>= 4.4.0 < 4.4.94.4.9
fortinetfortisandbox4.4.0 – 4.4.8
fortinetfortisandbox>= 5.0.0 < 5.0.65.0.6
fortinetfortisandbox5.0.0 – 5.0.5
fortinetfortisandbox_cloud>= 5.0.4 < 5.0.65.0.6
fortinetfortisandbox_cloud5.0.4 – 5.0.5
fortinetfortisandbox_paas>= 5.0.4 < 5.0.65.0.6
fortinetfortisandbox_paas5.0.4 – 5.0.5

Detection & IOCsextracted from sources · hover to see the quote

  • Target vector is specifically crafted HTTP requests to FortiSandbox WEB UI; monitor for anomalous/malformed HTTP requests to FortiSandbox management interfaces, particularly those targeting the 'start vnc' feature JSON input endpoint
  • The vulnerability is a second-order OS command injection via JSON input on the 'start vnc' feature; inspect JSON payloads sent to the VNC-related API endpoint for OS command injection characters/sequences
  • Active exploitation observed in the wild alongside CVE-2026-39813 and CVE-2026-39808; correlate FortiSandbox alerts across all three CVEs as threat actors are chaining them
  • The exploit for CVE-2026-25089 shows signs of AI-generated tooling and is noted as faulty; no working public exploit has been disclosed, but exploitation attempts are still being observed — treat any exploitation attempt as potentially automated/AI-assisted
  • CVE-2026-25089 is listed on CISA KEV with a remediation due date of 2026-07-19; CISA also requires forensic triage per BOD 26-04 for affected internet-exposed assets
  • ·Affected versions span multiple product lines: FortiSandbox 5.0.0–5.0.5, FortiSandbox 4.4.0–4.4.8, FortiSandbox 4.2 all versions, FortiSandbox Cloud 5.0.4–5.0.5, FortiSandbox PaaS 5.0.4–5.0.5; ensure detection/patching scope covers all three deployment types
  • ·CVSS score discrepancy between sources: NVD/THN report 9.1, while FortiGuard PSIRT reports 9.8 (Critical); use 9.8 for internal risk prioritization as it is the vendor's own assessment
  • ·The vulnerability is unauthenticated (no credentials required), making internet-exposed FortiSandbox WEB UI instances at highest risk; CISA BOD 26-04 guidance requires evaluating internet exposure of each asset

CVSS provenance

nvdv3.19.8CRITICALCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
vulncheck9.8CRITICAL
cisa9.8CRITICAL
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