Memory Buffer Bounds ErrorWeakness · CWE-119

CVE-2026-7750

HIGH · 8.8 CVSS v3.1 Published 2026-05-04
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 vulnerability was detected in Totolink N300RH 3.2.4-B20220812. This vulnerability affects the function setMacFilterRules of the file /cgi-bin/cstecgi.cgi of the component POST Request Handler. The manipulation of the argument mac_address results in buffer overflow. The attack may be launched remotely. The exploit is now public 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

Buffer overflow vulnerability in Totolink N300RH router firmware 3.2.4-B20220812 in the /cgi-bin/cstecgi.cgi CGI binary. The setMacFilterRules function fails to properly bounds-check the mac_address parameter during POST request handling, allowing memory corruption exploitable remotely.

MitigationApply vendor firmware patch when available; prior to patch, consider network segmentation to limit exposure to the router admin interface or disable mac filtering functionality if feasible.

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 firmware version
    Access the router admin web interface and look for firmware version information typically found under Status, System, or Firmware Upgrade pages. Alternatively, check the router label or documentation.
    Affected if Firmware version is 3.2.4-B20220812 or earlier (no fixed version specified in provided data)
  2. Locate the vulnerable CGI binary
    Attempt to access the file /cgi-bin/cstecgi.cgi on the router via HTTP/HTTPS request, or check router firmware filesystem if firmware dump is available.
    Affected if The /cgi-bin/cstecgi.cgi binary exists and is present on the device
  3. Verify MAC filter functionality is exposed
    Check if MAC filtering is an accessible feature in the router web interface under Wireless settings, Access Control, or MAC Filter sections. This feature must be enabled or configurable for the vulnerable code path to be reachable.
    Affected if MAC filtering feature is present and accessible in the router admin interface (the setMacFilterRules function handles requests to this feature)
  4. Confirm POST endpoint responds
    Send a crafted POST request to /cgi-bin/cstecgi.cgi with a mac_address parameter. A response (even an error) indicates the endpoint is active.
    Affected if The CGI endpoint accepts POST requests with mac_address parameter and processes them without crashing

User is affected if running Totolink N300RH firmware version 3.2.4-B20220812 with the /cgi-bin/cstecgi.cgi binary present and MAC filtering functionality accessible.

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 patch when available; prior to patch, consider network segmentation to limit exposure to the router admin interface or disable mac filtering functionality if feasible.

Have this fixed Scoped from the published advisory
  • Consultation3.0 h
  • Implementation4.0 h
  • Testing3.0 h
  • Review / QA2.0 h
12.0 hours of engineering $2,130
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Scan for this in your stack

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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-2026-7750 in production — separate from our analysis above.

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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
  • Verified mitigations, workarounds, and config changes
  • Version or environment caveats, and links to real fixes
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