CVE-2025-34037
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 · uneditedAn OS command injection vulnerability exists in various models of E-Series Linksys routers via the /tmUnblock.cgi and /hndUnblock.cgi endpoints over HTTP on port 8080. The CGI scripts improperly process user-supplied input passed to the ttcp_ip parameter without sanitization, allowing unauthenticated attackers to inject shell commands. This vulnerability was reported to be exploited in the wild by the "TheMoon" worm in 2014 to deploy a MIPS ELF payload, enabling arbitrary code execution on the router. Additionally, this vulnerability may affect other Linksys products to include, but not limited to, WAG/WAP/WES/WET/WRT-series router models and Wireless-N access points and routers. Exploitation evidence was observed by the Shadowserver Foundation on 2025-02-06 UTC.
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 confidenceOS command injection vulnerability in Linksys E-Series routers allows unauthenticated remote attackers to inject arbitrary shell commands via the ttcp_ip parameter in /tmUnblock.cgi and /hndUnblock.cgi endpoints on HTTP port 8080. The CGI scripts fail to sanitize user input, enabling TheMoon worm and similar malware to execute MIPS ELF payloads with root privileges.
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
- Authentication
- X
- User interaction
- None
- Scope
- X
CVSS:4.0/AV:N/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 checksWork through these to decide whether this CVE applies to you.
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Identify device modelAccess the router's admin web interface or check the device label/packaging to confirm the model is a Linksys E-Series, WAG, WAP, WES, WET, or WRT-series device.Affected if The device is any Linksys E-Series or related series router listed in the summary.
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Verify port 8080 is accessibleScan the router's IP address on port 8080 using a tool like nmap (nmap -p 8080 <router-ip>) or curl (curl http://<router-ip>:8080/). Check if the HTTP service responds on this port.Affected if Port 8080 returns an HTTP response, indicating the web interface is exposed on the alternate port.
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Check if vulnerable CGI endpoints respondSend a request to http://<router-ip>:8080/tmUnblock.cgi and/or http://<router-ip>:8080/hndUnblock.cgi using curl or a browser. Look for any response (even an error) rather than a connection timeout or 404.Affected if Either endpoint returns a response, indicating the vulnerable CGI scripts are present and accessible.
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Confirm ttcp_ip parameter is acceptedSend a benign test request to an affected endpoint with a test value for ttcp_ip, e.g., curl 'http://<router-ip>:8080/tmUnblock.cgi?ttcp_ip=127.0.0.1'. Observe if the parameter is processed (any response indicates the endpoint parses the parameter).Affected if The parameter is parsed and the endpoint returns a response, indicating user input is being processed without proper sanitization.
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Check firmware versionAccess the router admin interface (typically port 80 or 443) and navigate to the Administration or Firmware Upgrade section to view the current firmware version. Compare against any vendor release notes or security advisories for the model.Affected if The installed firmware version predates any vendor security patches for this vulnerability, or no patch is available for the device model.
A user is affected if they have a Linksys E-Series or related router with port 8080 exposed and the /tmUnblock.cgi or /hndUnblock.cgi endpoints responding to the ttcp_ip parameter without authentication.
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.
dbcve · scopedImmediately block external access to port 8080 at the network perimeter; apply available vendor firmware updates; if no patch exists, replace affected devices with supported hardware.
- 1. Block external access to port 8080/tcp on affected routers at the network perimeter/firewall. This endpoint should never be reachable from the internet.
- 2. If remote management is not required, disable the web-based administration interface entirely through the router's web UI under 'Administration' > 'Management' settings.
- 3. If remote management is required, change the default HTTP port 8080 to a non-standard port and restrict access to specific IP addresses via access control lists (ACLs).
- 4. Monitor network traffic for suspicious requests to /tmUnblock.cgi and /hndUnblock.cgi endpoints with unusual ttcp_ip parameter values (e.g., containing semicolons, pipes, or backticks).
- 5. Consider placing affected devices behind a properly configured perimeter firewall that blocks inbound connections to ports used for router management.
- 6. If the router is no longer supported by Linksys, replace it with a currently supported model that receives security updates.
Generated from the published advisory — verify against the referenced sources before acting.
- Consultation8.0 h
- Implementation16.0 h
- Testing8.0 h
- Review / QA4.0 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-2025-34037 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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- Version or environment caveats, and links to real fixes
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