Vulnerability in Nlnet Labs Unbound
CVE-2022-30698
NLnet Labs Unbound, up to and including version 1.16.1 is vulnerable to a novel type of the "ghost domain names" attack. The vulnerability works by targeting an Unbound instance. Unbound is queried for a subdomain of a rogue domain name. The rogue nameserver returns delegation information for the subdomain that updates Unbound's delegation cache. This action can be repeated before expiry of the delegation information by querying Unbound for a second level subdomain which the rogue nameserver provides new delegation information. Since Unbound is a child-centric resolver, the ever-updating child delegation information can keep a rogue domain name resolvable long after revocation. From version 1.16.2 on, Unbound checks the validity of parent delegation records before using cached delegation information.
EPSS: 0.009 (55.1th percentile) — read the EPSS interpretation.
CVSS v3 metric
CVSS v3 base score 6.5 (Medium). Vector: CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:N/A:N.
Affected products
- Nlnet Labs Unbound — versions unspecified
- Nlnetlabs Unbound
- Fedoraproject Fedora — versions 35, 36
Weakness classification (CWE)
Public proof-of-concept exploits
References
- sep@nlnetlabs.nl (Vendor Advisory)
- sep@nlnetlabs.nl (vendor-advisory)
- sep@nlnetlabs.nl (vendor-advisory)
- sep@nlnetlabs.nl (vendor-advisory, Third Party Advisory)
- sep@nlnetlabs.nl (mailing-list)
Frequently asked questions
- What is CVE-2022-30698?
- CVE-2022-30698 is a medium-severity vulnerability in Nlnet Labs Unbound, classified under Insufficient Session Expiration. CVSS score: 6.5/10. Published 2022-08-01.
- How severe is CVE-2022-30698?
- Medium severity. CVSS v3 base score is 6.5 out of 10.
- Is CVE-2022-30698 known to be exploited?
- 1 public proof-of-concept repositories are indexed. Not currently listed in the CISA KEV catalog.