Squid < 3.5.18 Host Header Handling Same-Origin Protection / Content Filtering Bypass (SQUID-2016:8)

high Nessus Plugin ID 108809
New! Plugin Severity Now Using CVSS v3

The calculated severity for Plugins has been updated to use CVSS v3 by default. Plugins that do not have a CVSS v3 score will fall back to CVSS v2 for calculating severity. Severity display preferences can be toggled in the settings dropdown.


The remote proxy server is potentially affected by a same-origin filtering bypass vulnerability.


According to its banner, the version of Squid running on the remote host is prior to 3.5.18. It is, therefore, potentially affected by a Host header same-origin filtering bypass vulnerability. A remote attacker could exploit this issue to poison the cache by forcing a Host header value past same-origin security protections to cause Squid to contact the wrong origin server.

Note that Nessus has not tested for this issue but has instead relied only on the application's self-reported version number.
Furthermore, the patch released to address this issue does not update the version given in the banner. If the patch has been applied properly, and the service has been restarted, then consider this to be a false positive.


Upgrade to Squid version 3.5.18 or later. Alternatively, apply the vendor-supplied patch.

See Also


Plugin Details

Severity: High

ID: 108809

File Name: squid_3_5_18.nasl

Version: 1.4

Type: remote

Family: Firewalls

Published: 4/3/2018

Updated: 12/17/2018

Dependencies: squid_version.nasl

Configuration: Enable paranoid mode

Risk Information

CVSS Score Source: CVE-2016-4554


Risk Factor: Medium

Score: 4.4


Risk Factor: Medium

Base Score: 5

Temporal Score: 3.7

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

Temporal Vector: E:U/RL:OF/RC:C


Risk Factor: High

Base Score: 8.6

Temporal Score: 7.5

Vector: CVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:C/C:N/I:H/A:N

Temporal Vector: E:U/RL:O/RC:C

Vulnerability Information

CPE: cpe:/a:squid-cache:squid

Required KB Items: installed_sw/Squid, Settings/ParanoidReport

Exploit Ease: No known exploits are available

Patch Publication Date: 5/6/2016

Vulnerability Publication Date: 5/6/2016

Reference Information

CVE: CVE-2016-4554