CVE-2011-4096 Denial of service in n/a
Remote attackers can cause a denial of service in Squid proxy servers by sending a crafted DNS reply with specific CNAME records.
- Exploited in the wild
- Not known
- Login needed
- Not needed
- Attackable
- Over the internet
- Victim action needed
- Not needed
- Fix
- Available
What is CVE-2011-4096?
CVE-2011-4096 is a medium-severity denial of service vulnerability in Squid-Cache Squid, published on 17 Nov 2011. An attacker can exploit it over the internet without logging in, with no action from the victim.
Official description
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.
Weakness: CWE-399
Which versions are affected by CVE-2011-4096?
It affects 1 product.
Linux distribution packages (4)
squid Red Hat:enterprise_linux:6::server | All versions | 7:3.1.10-1.el6_2.1 |
squid-debuginfo Red Hat:enterprise_linux:6::server | All versions | 7:3.1.10-1.el6_2.1 |
squid Red Hat:enterprise_linux:6::workstation | All versions | 7:3.1.10-1.el6_2.1 |
squid-debuginfo Red Hat:enterprise_linux:6::workstation | All versions | 7:3.1.10-1.el6_2.1 |
Products include Squid-Cache Squid.
How do I fix CVE-2011-4096?
Upgrade to a fixed version.
Upgrade, then put limits on request size, rate and nesting depth so one client cannot exhaust the service. More about Denial of service.
Is CVE-2011-4096 being exploited?
There is no known exploitation of CVE-2011-4096 in the wild and no public exploit code.
Other vulnerabilities in Squid-Cache Squid
- CVE-2025-62168 Squid vulnerable to information disclosure via authentication credential leakage in error handling
- CVE-2025-54574 Squid's URN Handling can lead to Buffer Overflow
- CVE-2026-33526 Squid vulnerable to Denial of Service in ICP Request handling
- CVE-2026-32748 Squid has Denial of Service in ICP Response handling
- CVE-2023-50269 SQUID-2023:10 Denial of Service in HTTP Request parsing
Sources
Also known as DSA-2381-1, GHSA-g3fq-pgcr-r7w6, RHSA-2011:1791.