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FortiosOperating system · Fortinet

CVE-2025-22251

MEDIUM · 5.3 CVSS v3.1 Published 2025-06-10
Fix available
A fix is available. Upgrade to 7.4.6 or later.
See remediation →
62/100
Remediation priority · Elevated
Remotely reachable No privileges Zero-click

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 restriction of communication channel to intended endpoints vulnerability [CWE-923] in FortiOS 7.6.0, 7.4.0 through 7.4.5, 7.2 all versions, 7.0 all versions, 6.4 all versions may allow an unauthenticated attacker to inject unauthorized sessions via crafted FGSP session synchronization packets.

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 · moderate confidence

This vulnerability in FortiOS allows unauthenticated attackers to inject unauthorized sessions via crafted FGSP (FortiGate Session Synchronization Protocol) packets. The issue stems from improper restriction of communication channels to intended endpoints (CWE-923), enabling attackers to bypass authentication and inject malicious session data into the HA synchronization mechanism.

MitigationUpgrade to a patched FortiOS version as specified in Fortinet's advisory. If immediate patching is not feasible, consider network segmentation to restrict FGSP traffic to trusted HA peer IP addresses only.

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, < 7.4.6= 7.6.0

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
None
Scope
Unchanged
Confidentiality
None
Integrity
Low
Availability
None

CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/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 FortiOS version
    Log into the FortiGate CLI and run 'get system status' or 'execute diagnosis system version' to retrieve the installed FortiOS firmware version
    Affected if The installed version falls within >= 6.4.0 and < 7.4.6, or is exactly 7.6.0
  2. Verify FGSP configuration
    Run 'get system ha' and look for FGSP-related settings, or use 'show system cluster-sync' to display FGSP cluster synchronization configuration
    Affected if FGSP (FortiGate Session Synchronization Protocol) is enabled and configured on the device
  3. Check FGSP peer definitions
    Run 'show system cluster-sync' to review configured FGSP peer IP addresses and interface bindings
    Affected if FGSP peers are defined and the configuration allows communication with untrusted or unspecified endpoints
  4. Review HA mode and FGSP overlay
    Run 'get system ha' and check if the device is operating in HA mode with FGSP session synchronization enabled, particularly in active-passive or active-active configurations
    Affected if HA is configured with FGSP session synchronization enabled, exposing the vulnerability vector

The device is affected if it runs FortiOS version 6.4.0 through 7.4.5, or exactly 7.6.0, AND has FGSP enabled as part of its HA configuration.

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 7.4.6 or later
Fixed in 7.4.6
Interim mitigation

Upgrade to a patched FortiOS version as specified in Fortinet's advisory. If immediate patching is not feasible, consider network segmentation to restrict FGSP traffic to trusted HA peer IP addresses only.

Recommended fix High confidence

FortiOS 7.4.6 or later (7.4.x branch); FortiOS 7.6.1 or later (7.6.x branch)

  1. 1. Identify the current FortiOS version using 'get system status' or through the web UI under Dashboard > Status
  2. 2. For FortiOS 7.4.x deployments: Upgrade to version 7.4.6 or later (7.4.6 is the minimum fixed release)
  3. 3. For FortiOS 7.6.0: Upgrade to version 7.6.1 or later when available from Fortinet support portal
  4. 4. For FortiOS 6.4.x, 7.0.x, and 7.2.x: Contact Fortinet support for specific patch availability as these branches may require elevated support or special patches
  5. 5. After upgrade, verify the FGSP configuration under System > Feature Visibility > FGSP (enable if needed), then navigate to System > FGSP to review session synchronization settings
  6. 6. Implement IP address restrictions on FGSP peers using 'set peer-ip' commands to further harden the communication channel
Caveat Standard FortiOS upgrade procedures apply - review release notes for known issues and ensure backup of configuration before upgrading

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

Fix this in Fortios Scoped from the published advisory
  • Consultation4.0 h
  • Implementation6.0 h
  • Testing4.0 h
  • Review / QA2.0 h
16.0 hours of engineering $2,840
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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-2025-22251 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