CVE-2009-3602 Security feature bypass in n/a
Remote attackers can downgrade secure DNS delegations by spoofing NSEC3 records, bypassing DNSSEC validation in Unbound.
- Exploited in the wild
- Not known
- Login needed
- Not needed
- Attackable
- Over the internet
- Victim action needed
- Not needed
- Fix
- Available
What is CVE-2009-3602?
CVE-2009-3602 is a high-severity vulnerability in Nlnetlabs Unbound, published on 13 Oct 2009. An attacker can exploit it over the internet without logging in, with no action from the victim.
Official description
Unbound before 1.3.4 does not properly verify signatures for NSEC3 records, which allows remote attackers to cause secure delegations to be downgraded via DNS spoofing or other DNS-related attacks in conjunction with crafted delegation responses.
Weakness: CWE-310
Which versions are affected by CVE-2009-3602?
It affects 1 product.
Products include Nlnetlabs Unbound.
How do I fix CVE-2009-3602?
Upgrade to a fixed version.
Is CVE-2009-3602 being exploited?
There is no known exploitation of CVE-2009-3602 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-2009-3602, DSA-1963-1, GHSA-3xrf-3v7w-582w.