CVE-2026-31849
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 · uneditedNexxt Solutions Nebula 300+ firmware through version 12.01.01.37 does not implement CSRF protections on state-changing endpoints such as /goform/setSysTools and other administrative interfaces. As a result, an attacker can craft malicious web requests that are executed in the context of an authenticated administrator’s browser, leading to unauthorized configuration changes, including enabling services or modifying system settings.
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 confidenceThe Nexxt Solutions Nebula 300+ router firmware lacks CSRF token validation on state-changing administrative endpoints including /goform/setSysTools. Attackers can exploit this by tricking authenticated administrators into visiting malicious pages, causing the browser to execute unauthorized configuration changes such as enabling services or modifying system settings.
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<= 12.01.01.37CVSS 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
- Required
- Scope
- Unchanged
- Confidentiality
- None
- Integrity
- High
- Availability
- None
CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:N/I:H/A:N
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 firmware versionAccess the router admin interface or check system information page to determine the installed firmware version. Common locations include the System Status, Administration, or Firmware Upgrade sections.Affected if The installed firmware version is 12.01.01.37 or earlier.
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Verify endpoint existenceCheck if the /goform/setSysTools administrative endpoint is accessible on the router. This can be done by attempting to access the URL directly or reviewing the router's web interface source code for form actions.Affected if The /goform/setSysTools endpoint exists and accepts requests.
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Inspect form for CSRF token presenceLog into the router admin interface and navigate to pages that modify system settings. View the page source (right-click, View Page Source) or inspect form elements to check if hidden CSRF tokens or similar anti-CSRF mechanisms are included in state-changing forms.Affected if Forms on state-changing pages lack CSRF token fields or anti-CSRF validation mechanisms.
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Check session cookie attributesUse browser developer tools (Application tab > Cookies) to inspect the session cookies set by the router admin interface. Look for SameSite and Secure attributes on authentication cookies.Affected if Session cookies do not have SameSite attributes configured or SameSite is set to None without Secure flag.
You are affected if your Nebula 300+ router runs firmware version 12.01.01.37 or earlier and the administrative forms lack CSRF token validation.
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 dataImplement anti-CSRF tokens on all state-changing endpoints and configure SameSite attributes for session cookies. Consider adding referrer header validation and requiring re-authentication for sensitive configuration changes.
- Consultation4.0 h
- Implementation12.0 h
- Testing6.0 h
- Review / QA3.0 h
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Free · runs locallyCheck whether your project pulls in CVE-2026-31849 — 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-2026-31849 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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