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Broadcom LinuxOperating system · Broadcom

CVE-2011-4503

HIGH · 7.5 CVSS v2.0 Published 2011-11-22
Mitigation only
No fix yet — a mitigation exists. There is no fixed release. A documented workaround reduces exposure in the meantime.
See remediation →
84/100
Remediation priority · High
Remotely reachable 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
The UPnP IGD implementation in Broadcom Linux on the Sitecom WL-111 allows remote attackers to establish arbitrary port mappings by sending a UPnP AddPortMapping action in a SOAP request to the WAN interface, related to an "external forwarding" vulnerability.

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

The Sitecom WL-111 router with Broadcom Linux contains a vulnerable UPnP IGD (Internet Gateway Device) implementation that allows remote attackers on the WAN side to send SOAP requests with AddPortMapping actions to create arbitrary port mappings. This enables external attackers to forward traffic from external ports to internal network hosts, effectively bypassing the device's firewall protections.

MitigationDisable UPnP functionality on the affected router; if the device is end-of-life and cannot receive firmware updates, replace it with a currently-supported router that receives security patches.

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
Broadcom LinuxOperating system
Affected:all versions
Wl 111Hardware / appliance
Affected:all versions

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
Authentication
None
Confidentiality
Partial
Integrity
Partial
Availability
Partial

AV:N/AC:L/Au:N/C:P/I:P/A:P

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 exact model number. Look for 'Sitecom WL-111' or any Broadcom Linux-based router.
    Affected if The device is a Sitecom WL-111 or a Broadcom Linux-based router with the vulnerable UPnP IGD implementation.
  2. Access the router web interface
    Log into the router admin panel (typically at 192.168.0.1 or 192.168.1.1) and navigate to the UPnP settings section, usually found under 'Advanced' or 'NAT' settings.
    Affected if UPnP is enabled in the router configuration.
  3. Verify UPnP service is listening on WAN
    From an external network, attempt to reach the UPnP IGD service on the router's WAN IP using port 1900 (SSDP) or the configured SOAP port. Use a tool like nmap: nmap -p 1900 <WAN_IP>
    Affected if The UPnP service is exposed and reachable from the WAN side (internet-facing).
  4. Test AddPortMapping SOAP action
    Send a crafted SOAP request to the UPnP IGD service on the WAN interface. Example using curl: curl -X POST '<WAN_IP>:1900/upnp/control/WANIPConnection' -H 'SOAPACTION: "urn:schemas-upnp-org:service:WANIPConnection:1#AddPortMapping"' -d '<?xml version="1.0" encoding="utf-8"?><s:Envelope xmlns:s="http://schemas.xmlsoap.org/soap/envelope/" s:encodingStyle="http://schemas.xmlsoap.org/soap/encoding/"><s:Body><u:AddPortMapping xmlns:u="urn:schemas-upnp-org:service:WANIPConnection:1"><NewRemoteHost></NewRemoteHost><NewExternalPort>12345</NewExternalPort><NewProtocol>TCP</NewProtocol><NewInternalPort>
    Affected if The SOAP request succeeds and creates a port mapping without authentication, confirming the vulnerability.
  5. Check existing port mappings from WAN
    Query the UPnP IGD GetGenericPortMappingEntry or GetExternalIP action from the WAN side to enumerate existing mappings: curl -X POST '<WAN_IP>:1900/upnp/control/WANIPConnection' -H 'SOAPACTION: "urn:schemas-upnp-org:service:WANIPConnection:1#GetExternalIP"'
    Affected if The router accepts and responds to these requests from the WAN, indicating UPnP is accessible externally.

A user is affected if they own a Sitecom WL-111 or Broadcom Linux-based router with UPnP enabled and the UPnP IGD service is exposed to or reachable from their WAN interface.

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

Disable UPnP functionality on the affected router; if the device is end-of-life and cannot receive firmware updates, replace it with a currently-supported router that receives security patches.

Fix this in Broadcom Linux Scoped from the published advisory
  • Consultation2.0 h
  • Implementation1.0 h
  • Testing2.0 h
  • Review / QA1.0 h
6.0 hours of engineering $1,060
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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-2011-4503 in production — separate from our analysis above.

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What this is

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What belongs here
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