Input validation error in Squid - CVE-2013-4123
Published: September 16, 2013 / Updated: May 1, 2026
Vulnerability identifier: #VU42563
CSH Severity: Medium
CVSS v4: 7.1 [CVSS:4.0/AV:N/AC:L/AT:N/PR:L/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N]
CVE-ID: CVE-2013-4123
CWE-ID: CWE-20
Exploitation vector: Remote access
Exploit availability:
Public exploit is available
Vulnerability details
The vulnerability allows a remote client to perform service disruption.
The vulnerability exists due to incorrect handling of HTTP requests in client_side_request.cc. A remote client can supply a crafted port number in a HTTP Host header and crash the server.
Affected software
Squid
How to mitigate CVE-2013-4123
Install update from vendor's website.
Squid - addressed in versions 3.2.13, 3.3.8