Cisco Linksys Router E4200/EA2700/EA3500/EA4500 backdoor

CVSS Meta Temp Score
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Current Exploit Price (≈)
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CTI Interest Score
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A vulnerability, which was classified as critical, has been found in Cisco Linksys Router E4200/EA2700/EA3500/EA4500 (Router Operating System). Affected by this issue is some unknown functionality. The manipulation with an unknown input leads to a backdoor vulnerability. Using CWE to declare the problem leads to CWE-912. The product contains functionality that is not documented, not part of the specification, and not accessible through an interface or command sequence that is obvious to the product's users or administrators. Impacted is confidentiality, integrity, and availability.

The weakness was released 07/01/2013 by Kyle Lovett as Update: Linksys EA2700, EA3500, E4200v2, EA4500 Unspecified unauthenticated remote access as confirmed mailinglist post (Bugtraq). The advisory is available at The vendor was not involved in the coordination of the public release. This vulnerability is handled as CVE-2013-5122 since 08/14/2013. The attack may be launched remotely. No form of authentication is required for exploitation. Technical details are unknown but a public exploit is available. This vulnerability is assigned to T1588.001 by the MITRE ATT&CK project.

A public exploit has been developed by phrag in HTTP GET Request and been published 2 years after the advisory. The exploit is available at It is declared as proof-of-concept. As 0-day the estimated underground price was around $5k-$25k. The code used by the exploit is:

curl -i
The advisory illustrates:
A HTTP GET request on port 8083 without authentication returns 200 OK and has full admin privileges

Upgrading to version eliminates this vulnerability.Addressing this vulnerability is possible by firewalling tcp/8083 (us-srv). The best possible mitigation is suggested to be upgrading to the latest version.

The vulnerability is also documented in the vulnerability database at X-Force (86480). is providing further details. Entries connected to this vulnerability are available at VDB-5620, VDB-7608 and VDB-12362.


  • Linksys EA2700 1.0.14
  • Linksys E4200 2.0.36
  • Linksys EA3500 1.0.30
  • Linksys EA4500 2.0.36








  • end of life (old version)

CPE 2.3info

CPE 2.2info


VulDB CVSS-B Score: 🔍
VulDB CVSS-BT Score: 🔍
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VulDB Meta Base Score: 8.5
VulDB Meta Temp Score: 8.2

VulDB Base Score: 7.3
VulDB Temp Score: 6.6
VulDB Vector: 🔍
VulDB Reliability: 🔍

NVD Base Score: 9.8
NVD Vector: 🔍



VulDB Base Score: 🔍
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Class: Backdoor
CWE: CWE-912

Local: No
Remote: Yes

Availability: 🔍
Access: Public
Status: Proof-of-Concept
Author: phrag
Programming Language: 🔍
Download: 🔍

EPSS Score: 🔍
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Threat Intelligenceinfo

Interest: 🔍
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Active APT Groups: 🔍


Recommended: Upgrade
Status: 🔍

0-Day Time: 🔍
Exploit Delay Time: 🔍

Upgrade: Linksys Router
Firewalling: 🔍


07/01/2013 🔍
07/01/2013 +0 days 🔍
07/04/2013 +3 days 🔍
08/14/2013 +41 days 🔍
04/10/2014 +239 days 🔍
06/04/2014 +55 days 🔍
05/17/2021 +2539 days 🔍



Advisory: Update: Linksys EA2700, EA3500, E4200v2, EA4500 Unspecified unauthenticated remote access
Researcher: Kyle Lovett
Status: Confirmed

CVE: CVE-2013-5122 (🔍)
X-Force: 86480
SecurityTracker: 1029769
Vulnerability Center: 43987 - Linksys Routers Remote Security Bypass Vulnerability in Administrative Console, Critical
OSVDB: 94768 - Cisco Linksys Multiple Router Unspecified Unauthenticated Remote Administration Access

scip Labs:
Misc.: 🔍
See also: 🔍


Created: 07/04/2013 12:33 PM
Updated: 05/17/2021 03:24 PM
Changes: 07/04/2013 12:33 PM (58), 07/09/2015 11:47 AM (9), 05/17/2021 03:18 PM (3), 05/17/2021 03:24 PM (18)
Complete: 🔍
Cache ID: 44:AB4:40


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