CVE-2009-4008 Denial of service in n/a
Remote attackers can cause a denial of service in Unbound DNS resolver by sending crafted queries to signed zones.
- Exploited in the wild
- Not known
- Login needed
- Not needed
- Attackable
- Over the internet
- Victim action needed
- Not needed
- Fix
- Available
What is CVE-2009-4008?
CVE-2009-4008 is a medium-severity denial of service vulnerability in Nlnetlabs Unbound, published on 2 Jun 2011. An attacker can exploit it over the internet without logging in, with no action from the victim.
Official description
Unbound before 1.4.4 does not send responses for signed zones after mishandling an unspecified query, which allows remote attackers to cause a denial of service (DNSSEC outage) via a crafted query.
Weakness: CWE-399
Which versions are affected by CVE-2009-4008?
It affects 1 product.
Products include Nlnetlabs Unbound.
How do I fix CVE-2009-4008?
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-2009-4008 being exploited?
There is no known exploitation of CVE-2009-4008 in the wild and no public exploit code.
Other vulnerabilities in Nlnetlabs Unbound
- CVE-2026-81642 Heap buffer overflow and possible Remote Code Execution when digesting DNSKEY
- CVE-2026-33278 Possible arbitrary code execution during DNSSEC validation
- CVE-2026-42944 Heap overflow with multiple NSID, COOKIE, PADDING EDNS options
- CVE-2026-42959 Crash during DNSSEC validation of malicious content
- CVE-2026-82717 CNAME synthesis could lead to heap corruption
Sources
Also known as DEBIAN-CVE-2009-4008, DSA-2243-1, GHSA-cjjv-pc59-mghf.