FortiwanApplication · Fortinet
CVE-2021-26102
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 relative path traversal vulnerability (CWE-23) in FortiWAN version 4.5.7 and below, 4.4 all versions may allow a remote non-authenticated attacker to delete files on the system by sending a crafted POST request. In particular, deleting specific configuration files will reset the Admin password to its default value.
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 confidenceA relative path traversal vulnerability (CWE-23) in FortiWAN versions 4.5.7 and below and 4.4 allows remote unauthenticated attackers to delete arbitrary files via crafted POST requests by manipulating path traversal sequences. The critical impact occurs when specific configuration files are deleted, which resets the administrator password to its default value, enabling full administrative access.
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
FortiwanApplication
>= 4.4.0, < 4.5.8CVSS 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
- High
- Availability
- High
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/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 checksWork through these to decide whether this CVE applies to you.
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Check FortiWAN versionAccess the FortiWAN management interface or check system information via CLI command 'fwcli -v' or through the web UI dashboard to identify the installed version numberAffected if The installed version is 4.4.0 through 4.5.7 (inclusive), meaning it falls within >= 4.4.0 and < 4.5.8
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Verify management interface network exposureReview firewall rules and network access control lists to determine if the FortiWAN management interface (typically ports 443 or 444) is accessible from untrusted networks or the internetAffected if The management interface is exposed to unauthenticated external network access without IP restrictions or VPN requirements
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Identify accessible management endpointsAttempt a harmless HTTP OPTIONS or HEAD request to the FortiWAN web interface from an authorized internal host to confirm the '/admin' or similar management paths are respondingAffected if The management endpoints respond to unauthenticated requests from non-admin network segments
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Check for password reset configuration filesIf you have administrative access, examine the FortiWAN configuration directory for the presence of the primary configuration files (typically in /var or /etc depending on installation) that govern administrator authenticationAffected if Configuration files controlling administrator passwords exist and could be targeted for deletion via path traversal
Your environment is affected if you are running FortiWAN version 4.4.0 through 4.5.7 and the management interface is accessible to unauthenticated network attackers who could exploit the path traversal to delete critical configuration files.
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 · scoped4.5.8
Upgrade FortiWAN to a patched version per vendor advisories. If immediate patching is not possible, restrict network access to the FortiWAN management interface to prevent unauthenticated external attackers from reaching the vulnerable endpoint.
FortiWAN version 4.5.8 or later
- Backup current FortiWAN configuration and settings
- Download FortiWAN version 4.5.8 or later from Fortinet's official support portal (fortiguard.fortinet.com)
- Upload the new firmware image through the FortiWAN web UI or CLI
- Apply the firmware upgrade and allow the system to reboot
- After reboot, verify the firmware version is 4.5.8 or later
- Log in with the default admin credentials and immediately change the admin password to a strong, unique value
- Restore the backed-up configuration if needed and verify system functionality
Generated from the published advisory — verify against the referenced sources before acting.
Fix this in Fortiwan
Scoped from the published advisory
- Consultation3.0 h
- Implementation4.0 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 $3,408.
Scan for this in your stack
Free · runs locallyCheck whether your project pulls in CVE-2021-26102 — 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-2021-26102 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
- No weaponised exploit code, or anything meant to cause harm
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