Stack-based Buffer OverflowWeakness · CWE-121

CVE-2026-44089

CRITICAL · 9.4 CVSS v4.0 Published 2026-06-23
Mitigation only
No fix yet — a mitigation exists. There is no fixed release. A documented workaround reduces exposure in the meantime.
See remediation →
99/100
Remediation priority · Urgent
No privileges 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
Totolink EX1200L router is vulnerable to Buffer Overflow in the login functionality in cgi-bin/cstecgi.cgi endpoint. This vulnerability could be exploited to cause the program to crash and to execute code remotely. This allows the attacker to perform actions as root including reading and editing data, as well as bricking the router. Because vendor contact attempts were unsuccessful, the vulnerability has only been confirmed in version 9.3.5u.6146_B20201023 but may also affect other versions.

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 buffer overflow vulnerability in the login functionality of the cgi-bin/cstecgi.cgi endpoint on Totolink EX1200L routers (version 9.3.5u.6146_B20201023) allows remote attackers to crash the device or execute arbitrary code with root privileges. This enables complete router compromise including data manipulation and device bricking.

MitigationSince no vendor patch is available, implement network segmentation to isolate affected routers, disable remote management interfaces from untrusted networks, and consider replacing affected devices with actively supported hardware.

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
Adjacent
Complexity
Low
Privileges
None
Authentication
X
User interaction
None
Scope
X

CVSS:4.0/AV:A/AC:L/AT:N/PR:N/UI:N/VC:H/VI:H/VA:H/SC:H/SI:H/SA:H/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X

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 router model
    Check the device label or web interface for the model name - look for Totolink EX1200L
    Affected if The device is not a Totolink EX1200L router, then this CVE does not apply
  2. Check the firmware version
    Access the router web interface and navigate to System Status or Firmware Upgrade page to view the installed firmware version, or check the version string in the firmware file if you have direct access
    Affected if The installed version matches or falls within the affected version range 9.3.5u.6146_B20201023 and potentially earlier versions
  3. Verify the web interface is enabled
    Attempt to access the router login page at http://<router-ip>/cgi-bin/cstecgi.cgi or http://<router-ip>/ - if a login page loads, the web interface is active
    Affected if The web interface is disabled or inaccessible, the attack surface is reduced but the device may still be vulnerable if re-enabled
  4. Check if remote management is exposed
    Determine if the router web interface is accessible from WAN/untrusted networks by checking Port Forwarding settings, Remote Management settings (often labeled WAN Access or Remote Access), or by attempting to access the router IP from an external network
    Affected if Remote management is enabled and the router is exposed to untrusted networks, it is directly vulnerable to remote exploitation

You are affected if you have a Totolink EX1200L router running firmware version 9.3.5u.6146_B20201023 (or similar) with the web interface accessible, especially if remote management is enabled.

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

Since no vendor patch is available, implement network segmentation to isolate affected routers, disable remote management interfaces from untrusted networks, and consider replacing affected devices with actively supported hardware.

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
Get help mitigating

An estimate, not a bill — we confirm scope with you before any work starts. Need it this week? Rush from $5,120.

Scan for this in your stack

Free · runs locally
dbcve dependency scanner

Check whether your project pulls in CVE-2026-44089 — 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 sources

Practitioner notes

Contributed

Peer-ranked notes from engineers who’ve handled CVE-2026-44089 in production — separate from our analysis above.

No notes yet

Be the first to add a field note for this CVE — a mitigation you’ve verified, a version caveat, or a link to a working fix. Sign in above to contribute.

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
  • No weaponised exploit code, or anything meant to cause harm
  • No spam, self-promotion, credentials, or personal data