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Memory Buffer Bounds ErrorWeakness · CWE-119

CVE-2026-11523

HIGH · 8.8 CVSS v3.1 Published 2026-06-08
Mitigation only
No fix yet — a mitigation exists. There is no fixed release. A documented workaround reduces exposure in the meantime.
See remediation →
94/100
Remediation priority · Urgent
Remotely reachable 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
A flaw has been found in Tenda W20E 15.11.0.6. This issue affects the function formPortalAuth of the file /goform/PortalAuth of the component Web Management Interface. Executing a manipulation of the argument gotoUrl can lead to stack-based buffer overflow. The attack can be launched remotely. The exploit has been published and may be used.

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 confidence

A stack-based buffer overflow vulnerability exists in the Tenda W20E router Web Management Interface (version 15.11.0.6). The flaw is in the formPortalAuth function within /goform/PortalAuth, where insufficient bounds checking on the gotoUrl parameter allows an attacker to overflow a stack-allocated buffer. This remote code execution vulnerability has a publicly available exploit.

MitigationApply vendor firmware updates when available; until then, disable or restrict access to the web management interface from untrusted networks, or implement network segmentation to limit exposure.

Verify against the referenced sources before acting — the references below are authoritative for this CVE, this summary is not.

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

CVSS:3.1/AV:N/AC:L/PR:L/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. Identify the device model
    Access the router admin interface or check the device label/marketing materials to confirm it is a Tenda W20E router. Alternatively, check the HTTP Server header or login page source for model identification.
    Affected if The device is not a Tenda W20E router, then it is not affected by this specific CVE.
  2. Check the firmware version
    Log into the router web management interface and navigate to System Settings > Firmware Upgrade or System Status page to view the current firmware version. Compare it to 15.11.0.6.
    Affected if The installed firmware version is exactly 15.11.0.6, indicating the specific affected version.
  3. Verify remote web management access is enabled
    Check the router firewall or remote management settings (usually under Advanced > Remote Management or Security settings). Determine if the web interface is accessible from WAN/outside networks rather than LAN only.
    Affected if Remote web management access is enabled and the interface is reachable from external networks, the vulnerability is directly exploitable.
  4. Confirm the PortalAuth endpoint exists
    Attempt to access the URI /goform/PortalAuth on the router (e.g., http://<router-ip>/goform/PortalAuth). A response (even an error) indicates the endpoint is present.
    Affected if The /goform/PortalAuth endpoint responds, indicating the vulnerable function is available.
  5. Check for signs of exploitation
    Review router logs for unusual POST requests to /goform/PortalAuth with abnormally long gotoUrl parameter values, or monitor network traffic for suspicious requests targeting this endpoint.
    Affected if Log entries or network traffic show requests to /goform/PortalAuth with unusually long gotoUrl parameters, suggesting attempted exploitation.

A Tenda W20E router running firmware version 15.11.0.6 with the web management interface exposed to untrusted networks and the /goform/PortalAuth endpoint accessible is affected by this CVE.

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.

From vendor data
Mitigation available No clean upgrade yet — mitigate in the meantime
Mitigation

Apply vendor firmware updates when available; until then, disable or restrict access to the web management interface from untrusted networks, or implement network segmentation to limit exposure.

Have this fixed Scoped from the published advisory
  • Consultation4.0 h
  • Implementation8.0 h
  • Testing4.0 h
  • Review / QA2.0 h
18.0 hours of engineering $3,200
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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-2026-11523 in production — separate from our analysis above.

No notes yet

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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
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  • Version or environment caveats, and links to real fixes
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