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FortiosOperating system · Fortinet

CVE-2025-31366

MEDIUM · 6.1 CVSS v3.1 Published 2025-10-14
Fix available
A fix is available. Upgrade to 7.4.9 / 7.6.4 or later.
See remediation →
68/100
Remediation priority · Elevated
Remotely reachable No privileges

Official description Straight from the sourceThe vendor's or NVD's own wording, published unedited. Authoritative, but often terse — it says what broke, rarely what to do.

NVD · unedited
An Improper Neutralization of Input During Web Page Generation vulnerability [CWE-79] vulnerability in Fortinet FortiOS 7.6.0 through 7.6.3, FortiOS 7.4.0 through 7.4.8, FortiOS 7.2 all versions, FortiOS 7.0 all versions, FortiOS 6.4 all versions, FortiProxy 7.6.0 through 7.6.3, FortiProxy 7.4 all versions, FortiProxy 7.2 all versions, FortiProxy 7.0 all versions, FortiSASE 25.2.a may allow an unauthenticated attacker to perform a reflected cross site scripting (XSS) via crafted HTTP requests.

Technical summary Written by usOur analysis, written from the advisory, the CVSS vector and the affected-version data. It adds context the advisory leaves out, and never invents facts that are not in the source.

dbcve analysis · high confidence

A reflected cross-site scripting (XSS) vulnerability (CWE-79) in Fortinet FortiOS, FortiProxy, and FortiSASE allows unauthenticated attackers to inject malicious scripts via crafted HTTP requests due to improper input neutralization during web page generation.

MitigationApply available vendor patches for affected FortiOS (7.0-7.6.3), FortiProxy (7.0-7.6.3), and FortiSASE versions. Until patched, consider restricting access to affected web interfaces or implementing WAF rules to filter malicious request patterns.

Verify against the referenced sources before acting — the references below are authoritative for this CVE, this summary is not.

Affected products & versions What the vendor confirmedThe version ranges the vendor confirmed as vulnerable. If your version sits inside a range here, treat yourself as exposed until you have upgraded.

NVD · CPE data
FortiosOperating system
Affected:>= 6.4.0, < 7.4.9>= 7.6.0, < 7.6.4
FortiproxyApplication
Affected:>= 7.0.0, < 7.6.4
FortisaseApplication
Affected:= 25.3.40

CVSS breakdown How the score is builtThe industry scoring standard. It rates how the flaw is reached, what it takes to exploit, and what an attacker gains — the score is derived from those, not the other way round.

From the vector
Attack vector
Network
Complexity
Low
Privileges
None
User interaction
Required
Scope
Changed
Confidentiality
Low
Integrity
Low
Availability
None

CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:L/A:N

Am I affected? How to checkSteps we derive from the advisory and the affected-version data, so you can decide whether this CVE reaches your setup. They are a guide, not a scan — your own configuration is the authority.

dbcve checks

Work through these to decide whether this CVE applies to you.

  1. Identify Fortinet product and version
    Run CLI command 'get system status' or access the web GUI and check System > Settings > About. Confirm whether the device is FortiOS, FortiProxy, or FortiSASE and note the exact version number.
    Affected if The product version falls within FortiOS >= 6.4.0 and < 7.4.9 OR FortiOS >= 7.6.0 and < 7.6.4 OR FortiProxy >= 7.0.0 and < 7.6.4 OR FortiSASE version 25.3.40.
  2. Verify web interface is enabled
    In the web GUI, go to System > Settings > Administration Settings. Check if 'HTTPS server' is enabled. Alternatively, from CLI run 'get system interface' to list enabled interfaces and verify HTTP/HTTPS access is permitted.
    Affected if The administrative web interface (HTTP/HTTPS) is accessible to users on any network segment.
  3. Confirm administrative access is not restricted
    Review the administrative access settings on each interface ( wan1, wan2, internal, etc.) via CLI: 'show system interface' or via GUI: Network > Interfaces. Determine if management access is open to untrusted networks.
    Affected if The web interface is reachable from untrusted networks (such as the internet) without IP restriction.

You are affected if your FortiOS, FortiProxy, or FortiSASE version is within the affected ranges AND the web administrative interface is enabled and accessible.

Generated from the published advisory. Verify against your own configuration.

Check your environment

Paste your version and any relevant configuration and it will be compared against the affected criteria above. Do not include secrets or credentials.

AI-assisted, checked against the advisory. Informational, not a guarantee.

Remediation Closing itWhat it takes to close this. Where a vendor fix exists we point at it; where none exists we say so plainly, and can build one. Effort estimates are scoped from the advisory, not from your codebase.

dbcve · scoped
Upgrade available Upgrade to 7.4.9 / 7.6.4 or later
Fixed in 7.4.97.6.4
Interim mitigation

Apply available vendor patches for affected FortiOS (7.0-7.6.3), FortiProxy (7.0-7.6.3), and FortiSASE versions. Until patched, consider restricting access to affected web interfaces or implementing WAF rules to filter malicious request patterns.

Recommended fix High confidence

FortiOS 7.4.9+ (or 7.6.4+ depending on branch); FortiProxy 7.6.4+; FortiSASE 25.3.41+

  1. Identify current FortiOS, FortiProxy, or FortiSASE version using: get system status or fortios -i version
  2. For FortiOS 7.4.x users: Upgrade to FortiOS 7.4.9 or later
  3. For FortiOS 7.6.x users: Upgrade to FortiOS 7.6.4 or later
  4. For FortiOS 6.4.x, 7.0.x, 7.2.x users: Upgrade to the minimum fixed version for your branch (7.4.9 for 7.4 branch, 7.6.4 for 7.6 branch) - note: older branches may require intermediate upgrades
  5. For FortiProxy 7.x users: Upgrade to FortiProxy 7.6.4 or later
  6. For FortiSASE 25.3.40 users: Upgrade to FortiSASE 25.3.41 or later (or the next available stable release)
  7. After upgrade, verify the fix using: execute diagnose debug application httpsd -1 to confirm no XSS-related errors
Caveat Review Fortinet release notes for your upgrade path - upgrading across major versions (e.g., 6.4 to 7.4) may require intermediate steps and could have configuration/compatibility considerations

Generated from the published advisory — verify against the referenced sources before acting.

Fix this in Fortios Scoped from the published advisory
  • Consultation3.0 h
  • Implementation4.0 h
  • Testing4.0 h
  • Review / QA2.0 h
13.0 hours of engineering $2,280
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References Go to the primary sourcePrimary sources — vendor advisories, patches and trackers. Where our summary and a reference disagree, the reference wins.

Primary sources

Practitioner notes

Contributed

Peer-ranked notes from engineers who’ve handled CVE-2025-31366 in production — separate from our analysis above.

No notes yet

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What this is

A place for practitioners to share what actually worked: a mitigation you’ve tested, a configuration change, a version- or environment-specific caveat, or a link to a verified patch. The most useful notes rise to the top as peers upvote them, so the signal stays high.

What belongs here
  • Verified mitigations, workarounds, and config changes
  • Version or environment caveats, and links to real fixes
  • No weaponised exploit code, or anything meant to cause harm
  • No spam, self-promotion, credentials, or personal data