FortiauthenticatorApplication · Fortinet
CVE-2023-26208
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 · uneditedA improper restriction of excessive authentication attempts vulnerability [CWE-307] in Fortinet FortiAuthenticator 6.4.x and before allows a remote unauthenticated attacker to partially exhaust CPU and memory via sending numerous HTTP requests to the login form.
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 confidenceFortiAuthenticator 6.4.x and prior versions lack proper rate limiting on the login form, allowing unauthenticated remote attackers to send numerous HTTP requests that partially exhaust CPU and memory resources, causing denial of service.
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
FortiauthenticatorApplication
>= 5.4.0, < 6.5.0CVSS 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
- None
- Availability
- Low
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:L
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 checksWork through these to decide whether this CVE applies to you.
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Check FortiAuthenticator versionLog into the FortiAuthenticator CLI and run: `get system status` OR access the web UI and navigate to System > Settings > General to view the firmware versionAffected if The version is 6.4.x or prior, or any version >= 5.4.0 and < 6.5.0
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Inspect login page rate limiting configurationIn the FortiAuthenticator web UI, navigate to Authentication > Settings > Rate Limiting (or similar path depending on version) to verify if rate limiting is enabled on the login endpointAffected if Rate limiting on the login form is not enabled or not configured
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Review authentication policy for throttling settingsCheck Authentication > Policies to see if there are any rate limiting, lockout, or throttling rules applied to the login authentication policyAffected if No rate limiting or account lockout policies are defined for failed login attempts
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Check for external WAF or proxy rate limitingInspect any upstream web application firewall, load balancer, or reverse proxy in front of FortiAuthenticator to determine if rate limiting is being handled externallyAffected if No external rate limiting protection exists and FortiAuthenticator version is vulnerable
You are affected if FortiAuthenticator is version 6.4.x or prior (>= 5.4.0 and < 6.5.0) AND rate limiting on the login endpoint is not enabled or configured.
Generated from the published advisory. Verify against your own configuration.
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 · scoped6.5.0
Implement rate limiting or throttling on the login endpoint, potentially combined with CAPTCHA or IP-based blocking after failed attempts, and upgrade to a patched version if available.
6.5.0 or later
- Upgrade FortiAuthenticator to version 6.5.0 or later to remediate this vulnerability.
- After upgrading, verify that the authentication rate limiting is functioning correctly by reviewing system resources under load.
Generated from the published advisory — verify against the referenced sources before acting.
Fix this in Fortiauthenticator
Scoped from the published advisory
- Consultation3.0 h
- Implementation6.0 h
- Testing3.0 h
- Review / QA2.0 h
An estimate, not a bill — we confirm scope with you before any work starts. Need it this week? Rush from $3,984.
Scan for this in your stack
Free · runs locallyCheck whether your project pulls in CVE-2023-26208 — or any other known-vulnerable package — straight from your lock files. Free and open source; it runs locally and uploads nothing.
References Go to the primary sourcePrimary sources — vendor advisories, patches and trackers. Where our summary and a reference disagree, the reference wins.
Primary sourcesPractitioner notes
ContributedPeer-ranked notes from engineers who’ve handled CVE-2023-26208 in production — separate from our analysis above.
The advisory tells you what broke. It rarely tells you what actually worked. If you’ve dealt with this one, that detail is what the next engineer is searching for.
- The version that genuinely resolved it — not the one the vendor claimed
- A config change or rule that shut the vector down
- A gotcha in the upgrade path that cost you an afternoon
No notes yet
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- Verified mitigations, workarounds, and config changes
- Version or environment caveats, and links to real fixes
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