Vulnerability in Nlnet Labs Unbound

CVE-2022-30699

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 rogue domain name when the cached delegation information is about to expire. The rogue nameserver delays the response so that the cached delegation information is expired. Upon receiving the delayed answer containing the delegation information, Unbound overwrites the now expired entries. This action can be repeated when the delegation information is about to expire making the rogue delegation information ever-updating. From version 1.16.2 on, Unbound stores the start time for a query and uses that to decide if the cached delegation information can be overwritten.

Published · last modified .

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.

EPSS exploit prediction

EPSS: 0.011 (64.9th percentile), scored .

Low probability of exploitation in the next 30 days, but still tracked. 65th percentile — 64.9% of CVEs in the catalogue have a lower EPSS than this one. How to read EPSS.

EPSS trend (30 days)EPSS over the last 30 days for CVE-2022-30699: held from 0.011 to 0.011.

EPSS over last 30 days · oldest: 0.011 · newest: 0.011 · change: +0.001

Affected products

Weakness classification (CWE)

References

Frequently asked questions

What is CVE-2022-30699?
CVE-2022-30699 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-2022-30699?
Medium severity. CVSS v3 base score is 6.5 out of 10.