CVE-2025-50399
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 · uneditedFAST FAC1200R F400_FAC1200R_Q is vulnerable to Buffer Overflow in the function sub_80435780 via the parameter password.
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 confidenceA buffer overflow vulnerability exists in the FAST FAC1200R F400_FAC1200R_Q router firmware. The overflow occurs in function sub_80435780 when processing the password parameter, allowing potential remote attackers to execute arbitrary code or cause denial of service given the critical CVSS score of 9.8.
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= f400_fac1200r_qCVSS 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
- High
- Integrity
- High
- Availability
- High
CVSS:3.1/AV:N/AC:L/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 checksWork through these to decide whether this CVE applies to you.
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Identify the device modelCheck the router label or login to the admin interface to confirm the model is FAST FAC1200R F400_FAC1200R_QAffected if The device model is FAST FAC1200R F400_FAC1200R_Q and firmware version is f400_fac1200r_q
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Check firmware versionAccess the router admin panel (typically at 192.168.1.1) and look under System Status or Firmware Upgrade to view the installed firmware versionAffected if The firmware version is exactly f400_fac1200r_q (the only affected version)
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Verify remote management is accessibleCheck router settings under Advanced or Security settings for Remote Management/Web Management access - determine if the admin interface is reachable from the WAN/internetAffected if Remote management interface is enabled and accessible from external networks (required for remote exploitation)
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Confirm password change functionality is exposedAttempt to access the router login page or password change endpoint from both LAN and WAN interfaces to verify the password parameter handler is reachableAffected if The password parameter processing function (sub_80435780) is accessible through the web interface
You are affected if you have a FAST FAC1200R F400_FAC1200R_Q router running firmware version f400_fac1200r_q with remote management accessible from untrusted networks.
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.
From vendor dataApply vendor firmware updates when available; until then, disable remote management interfaces, restrict administrative access to trusted IP addresses only, and monitor for indicators of compromise.
- Consultation4.0 h
- Implementation12.0 h
- Testing8.0 h
- Review / QA4.0 h
An estimate, not a bill — we confirm scope with you before any work starts. Need it this week? Rush from $7,808.
Scan for this in your stack
Free · runs locallyCheck whether your project pulls in CVE-2025-50399 — 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-2025-50399 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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