CVE-2026-31255
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 command injection vulnerability exists in Tenda AC18 V15.03.05.05_multi. The vulnerability is located in the /goform/SetSambaCfg interface, where improper handling of the guestuser parameter allows attackers to execute arbitrary system commands.
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 command injection vulnerability in Tenda AC18 firmware V15.03.05.05_multi allows remote attackers to execute arbitrary system commands via the /goform/SetSambaCfg interface. The guestuser parameter is not properly sanitized, enabling OS command injection with CVSS 9.8 (Critical).
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= 15.03.05.05CVSS 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 modelAccess the router's web management interface or check the device label to confirm it is a Tenda AC18 router.Affected if The device is not a Tenda AC18 router.
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Check the firmware versionLog into the router's web interface and navigate to the System/Firmware or Administration section to view the firmware version. Alternatively, use the command 'cat /proc/version' or 'ver' if you have telnet/SSH access.Affected if The firmware version is 15.03.05.05 exactly.
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Verify the web management interface is accessibleAttempt to access the router's IP address (typically 192.168.0.1) via HTTP/HTTPS from the network.Affected if The web interface is accessible and responds.
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Confirm the Samba configuration interface existsCheck if the /goform/SetSambaCfg endpoint is reachable by attempting to access it or reviewing the router's web interface for Samba/Storage sharing settings.Affected if The SetSambaCfg interface or Samba sharing feature is present and accessible.
A user is affected if they have a Tenda AC18 router running firmware version 15.03.05.05 with the web management interface and Samba configuration feature accessible.
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 patch if available; otherwise restrict access to the router's web management interface to trusted IPs or disable the affected Samba configuration functionality.
- Consultation2.0 h
- Implementation4.0 h
- Testing3.0 h
- Review / QA1.0 h
An estimate, not a bill — we confirm scope with you before any work starts. Need it this week? Rush from $2,800.
Scan for this in your stack
Free · runs locallyCheck whether your project pulls in CVE-2026-31255 — 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-2026-31255 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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