Public Date:
750316: CVE-2011-4096 squid: Invalid free by processing CNAME DNS record pointing to another CNAME record pointing to an empty A-record

The MITRE CVE dictionary describes this issue as:

The idnsGrokReply function in Squid before 3.1.16 does not properly free memory, which allows remote attackers to cause a denial of service (daemon abort) via a DNS reply containing a CNAME record that references another CNAME record that contains an empty A record.

Find out more about CVE-2011-4096 from the MITRE CVE dictionary dictionary and NIST NVD.


This issue did not affect the versions of squid as shipped with Red Hat Enterprise Linux 4 and 5 as they did not include IPv6 support. This issue was introduced with the addition of IPv6 support in Squid 3.1 (in the changes made to the idnsGrokReply function).

CVSS v2 metrics

Base Score 3.3
Base Metrics AV:A/AC:L/Au:N/C:N/I:N/A:P
Access Vector Adjacent Network
Access Complexity Low
Authentication None
Confidentiality Impact None
Integrity Impact None
Availability Impact Partial

Find out more about Red Hat support for the Common Vulnerability Scoring System (CVSS).

Red Hat Security Errata

Platform Errata Release Date
Red Hat Enterprise Linux 6 (squid) RHSA-2011:1791 2011-12-06

Affected Packages State

Platform Package State
Red Hat Enterprise Linux 5 squid Not affected
Red Hat Enterprise Linux 4 squid Not affected

Last Modified