CVE-2011-4096

CVE-2011-4096 is a medium-severity vulnerability in Squid-cache Squid with a CVSS 2.0 base score of 5.0. Its EPSS exploit-prediction score of 37% places it in the 98th percentile, indicating an elevated likelihood of exploitation. The underlying weakness is classified as CWE-399.

Key facts

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.

Frequently asked questions

What is CVE-2011-4096?
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.
How severe is CVE-2011-4096?
CVE-2011-4096 has a CVSS 2.0 base score of 5.0, rated medium severity.
Is CVE-2011-4096 being actively exploited?
It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 37% (98th percentile), an estimate of the probability of exploitation in the next 30 days.
What products are affected by CVE-2011-4096?
CVE-2011-4096 primarily affects Squid-cache Squid. In total, 87 product configurations (CPEs) are listed as vulnerable; see the affected-products list for the exact versions.
How do I fix CVE-2011-4096?
Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround.
When was CVE-2011-4096 published?
CVE-2011-4096 was published on 2011-11-17 and last updated on 2026-06-16.

References

Affected products (87)

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