CVE-2016-4553

Severity: high (CVSS 8.6 v3.0)
Exploited in the wild: not listed in CISA KEV
EPSS: 80.0% probability of exploitation in the next 30 days
Public exploit or detection template: none known
Published: 2016-05-10 · updated 2026-06-17
Weakness: CWE-345

Description

client_side.cc in Squid before 3.5.18 and 4.x before 4.0.10 does not properly ignore the Host header when absolute-URI is provided, which allows remote attackers to conduct cache-poisoning attacks via an HTTP request.

Affected products

Canonical Ubuntu Linux: 12.04, 14.04, 15.10, 16.04
Oracle Corporation Oracle Linux: 7
Squid: through 3.5.17; 4.0.1, 4.0.2, 4.0.3, 4.0.4, 4.0.5, 4.0.6 (+3)

References

http://bugs.squid-cache.org/show_bug.cgi?id=4501
http://lists.opensuse.org/opensuse-security-announce/2016-08/msg00010.html
http://lists.opensuse.org/opensuse-security-announce/2016-08/msg00040.html
http://lists.opensuse.org/opensuse-updates/2016-08/msg00069.html
http://www.debian.org/security/2016/dsa-3625
http://www.oracle.com/technetwork/topics/security/linuxbulletinapr2016-2952096.html
http://www.securitytracker.com/id/1035768
http://www.squid-cache.org/Advisories/SQUID-2016_7.txt
http://www.squid-cache.org/Versions/v3/3.5/changesets/squid-3.5-14039.patch
http://www.ubuntu.com/usn/USN-2995-1
https://access.redhat.com/errata/RHSA-2016:1139
https://access.redhat.com/errata/RHSA-2016:1140

Get alerted when CVE-2016-4553 or the next vulnerability affects your stack