CVE-2011-4528

CVE-2011-4528 is a medium-severity vulnerability in Unbound with a CVSS 2.0 base score of 5.0. It is not currently listed as actively exploited by CISA, and its EPSS exploit-prediction score is low. The underlying weakness is classified as CWE-399.

Key facts

Description

Unbound before 1.4.13p2 attempts to free unallocated memory during processing of duplicate CNAME records in a signed zone, which allows remote DNS servers to cause a denial of service (daemon crash) via a crafted response.

Frequently asked questions

What is CVE-2011-4528?
Unbound before 1.4.13p2 attempts to free unallocated memory during processing of duplicate CNAME records in a signed zone, which allows remote DNS servers to cause a denial of service (daemon crash) via a crafted response.
How severe is CVE-2011-4528?
CVE-2011-4528 has a CVSS 2.0 base score of 5.0, rated medium severity.
Is CVE-2011-4528 being actively exploited?
It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 3% (85th percentile), an estimate of the probability of exploitation in the next 30 days.
What products are affected by CVE-2011-4528?
CVE-2011-4528 primarily affects Unbound. In total, 41 product configurations (CPEs) are listed as vulnerable; see the affected-products list for the exact versions.
How do I fix CVE-2011-4528?
Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround.
When was CVE-2011-4528 published?
CVE-2011-4528 was published on 2011-12-20 and last updated on 2026-06-16.

References

Affected products (41)

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