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FortiosOperating system · Fortinet

CVE-2026-22153

HIGH · 8.1 CVSS v3.1 Published 2026-02-10
Fix available
A fix is available. Upgrade to 7.6.5 or later.
See remediation →
90/100
Remediation priority · Urgent
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 Authentication Bypass by Primary Weakness vulnerability [CWE-305] vulnerability in Fortinet FortiOS 7.6.0 through 7.6.4 may allow an unauthenticated attacker to bypass LDAP authentication of Agentless VPN or FSSO policy, when the remote LDAP server is configured in a specific way.

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

FortiOS 7.6.0-7.6.4 contains an authentication bypass vulnerability (CWE-305) where an unauthenticated attacker can bypass LDAP authentication used in Agentless VPN or FSSO (Fortinet Single Sign-On) policies. The vulnerability is triggered when the remote LDAP server is configured in a specific, unspecified way, allowing unauthenticated access to resources protected by the affected authentication policies.

MitigationUpgrade FortiOS to version 7.6.5 or later per Fortinet's security advisory. Additionally, audit LDAP server configurations in Agentless VPN and FSSO policies to identify and remediate the specific configuration that enables this bypass.

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:>= 7.6.0, < 7.6.5

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
High
Privileges
None
User interaction
None
Scope
Unchanged
Confidentiality
High
Integrity
High
Availability
High

CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:H

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. Check FortiOS version
    Run 'get system status' or 'fortios -v' via CLI to display the installed FortiOS version
    Affected if Version is 7.6.0 through 7.6.4 inclusive (version >= 7.6.0 and < 7.6.5)
  2. Identify Agentless VPN policies using LDAP
    Run 'show vpn ssl web portal' and review SSL VPN configuration for Agentless VPN settings; check 'get vpn ssl web portal' for portals with LDAP authentication configured
    Affected if Agentless VPN is configured and uses LDAP as the authentication method
  3. Identify FSSO policies using LDAP
    Run 'get user fsso' and 'show user fsso' to list configured FSSO collectors; review 'get vpn ssl settings' and 'config user ldap' to identify FSSO policies that integrate with LDAP servers
    Affected if FSSO (Fortinet Single Sign-On) is configured and uses LDAP authentication
  4. Review LDAP server configurations referenced by affected policies
    Run 'config user ldap' then 'show' to list all LDAP server configurations; examine server addresses, bind types, and DN patterns for policies identified in steps 2 and 3
    Affected if LDAP server is configured in the specific manner that enables the bypass (exact configuration specifics unknown - compare your LDAP settings against Fortinet documentation for hardening guidance)

Environment is affected if running FortiOS 7.6.0-7.6.4 AND either Agentless VPN or FSSO policies are configured with LDAP authentication, regardless of LDAP server configuration specifics since the vulnerable configuration pattern is not fully disclosed.

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 7.6.5 or later
Fixed in 7.6.5
Interim mitigation

Upgrade FortiOS to version 7.6.5 or later per Fortinet's security advisory. Additionally, audit LDAP server configurations in Agentless VPN and FSSO policies to identify and remediate the specific configuration that enables this bypass.

Recommended fix High confidence

FortiOS 7.6.5

  1. 1. Check current FortiOS version using 'get system status' or 'show system global' CLI command
  2. 2. Download FortiOS 7.6.5 or later firmware from Fortinet support portal
  3. 3. Upload the firmware to the FortiOS device via web UI (System > Firmware) or CLI ('execute restore image')
  4. 4. Reboot the device to complete the firmware upgrade
  5. 5. After upgrade, verify the new version with 'get system status'
  6. 6. Test LDAP authentication for Agentless VPN and FSSO policies to confirm the vulnerability is resolved
Caveat Standard minor version upgrade within 7.6.x branch; review Fortinet release notes for any configuration changes

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

Fix this in Fortios Scoped from the published advisory
  • Consultation2.0 h
  • Implementation4.0 h
  • Testing6.0 h
  • Review / QA3.0 h
15.0 hours of engineering $2,560
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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-2026-22153 in production — separate from our analysis above.

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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