CVE-2026-4254
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 weakness has been identified in Tenda AC8 up to 16.03.50.11. This vulnerability affects the function doSystemCmd of the file /goform/SysToolChangePwd of the component HTTP Endpoint. This manipulation of the argument local_2c causes stack-based buffer overflow. The attack can be initiated remotely. The exploit has been made available to the public and could be used for attacks.
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 confidenceStack-based buffer overflow in Tenda AC8 router's HTTP endpoint (/goform/SysToolChangePwd) in the doSystemCmd function. The local_2c argument is not properly bounds-checked before being used, allowing an attacker to overwrite stack memory and potentially achieve remote code execution with the privileges of the web server process.
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<= 16.03.50.11CVSS 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.
-
Confirm device is Tenda AC8 modelAccess router web interface and check the device model in System Status or Hardware Info page, or check product label on the device itselfAffected if Device is not a Tenda AC8 router - this CVE does not apply
-
Check installed firmware versionNavigate to router web UI (typically 192.168.0.1), go to System Status or Firmware Upgrade page, and note the firmware version displayedAffected if Firmware version is 16.03.50.11 or lower (or any version <= 16.03.50.11)
-
Verify HTTP service is accessibleAttempt to access http://router-ip/goform/SysToolChangePwd from a browser or curl command - if page loads or returns any response, the HTTP service is activeAffected if HTTP service returns a response (even error) - the vulnerable endpoint is reachable
-
Check if remote/Internet management is enabledIn router web UI, go to System Settings or Administration section, look for Remote Management, Web Management, or similar setting. Check if it allows access from WAN/Internet IP addressesAffected if Remote management from WAN is enabled - increases exposure to external attackers
Device is affected if it is a Tenda AC8 router running firmware version 16.03.50.11 or lower with the HTTP interface accessible (especially from remote 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 available firmware update from Tenda; if unavailable, disable remote management access or place device behind a firewall to limit exposure to internal networks only.
- Consultation4.0 h
- Implementation8.0 h
- Testing6.0 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 $6,176.
Scan for this in your stack
Free · runs locallyCheck whether your project pulls in CVE-2026-4254 — 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-2026-4254 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
Be the first to add a field note for this CVE — a mitigation you’ve verified, a version caveat, or a link to a working fix. Sign in above to contribute.
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.
- 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