CVE-2026-36799
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 · uneditedShenzhen Tenda Technology Co., Ltd Tenda G0 v15.11.0.5 was discovered to contain a buffer overflow in the portalAuth parameter of the formPortalAuth function. This vulnerability allows attackers to cause a Denial of Service (DoS) via a crafted HTTP request.
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 buffer overflow vulnerability exists in the formPortalAuth function of Tenda G0 router firmware v15.11.0.5. The portalAuth HTTP parameter fails to properly validate input length before copying data into a fixed-size buffer, allowing an attacker to trigger a denial of service by sending a specially crafted HTTP request with an oversized payload.
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
- None
- User interaction
- None
- Scope
- Unchanged
- Confidentiality
- None
- Integrity
- None
- Availability
- High
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/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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Confirm Tenda G0 router modelAccess the router's web interface or physically inspect the device label to verify the exact model is Tenda G0.Affected if The device is not a Tenda G0 router.
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Identify installed firmware versionLog into the router web management interface and navigate to the System or Firmware settings to view the running firmware version. Compare this version to v15.11.0.5.Affected if The installed firmware version is 15.11.0.5 or falls within an unpatched version range.
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Verify HTTP management interface is enabledAttempt to access the router's web interface via HTTP on common ports (80, 8080, or the configured management port). Confirm the interface responds to requests.Affected if The router's web management interface is accessible on the network.
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Check if portal authentication feature is activeReview the router's configuration to determine if the portal authentication or captive portal feature is enabled, which exposes the formPortalAuth function.Affected if The portal authentication feature is enabled and the formPortalAuth endpoint is reachable.
If the device is a Tenda G0 router running firmware v15.11.0.5 with the web management interface and portal authentication feature exposed, the environment is likely affected by this buffer overflow vulnerability.
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 the vendor-supplied firmware patch for CVE-2026-36799 to upgrade from v15.11.0.5. If no patch is available, consider network segmentation to limit exposure of the router management interface or disable the portalAuth functionality until a fix is released.
- Consultation2.0 h
- Implementation1.0 h
- Testing2.0 h
- Review / QA1.0 h
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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 sourcesPractitioner notes
ContributedPeer-ranked notes from engineers who’ve handled CVE-2026-36799 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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