# CVE-2026-42955

## Summary

- **CVE ID:** CVE-2026-42955
- **Severity:** LOW
- **CVSS Score:** 3.7 (CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:L/A:N)
- **CWE:** CWE-672
- **Published:** Jul 22, 2026
- **Last Modified:** Jul 24, 2026

## Description

In NLnet Labs Unbound 1.16.2 up to and including 1.25.1, a similar vulnerability as with CVE-2026-40622 in the 'ghost domain names' family of attacks was found in Unbound that could extend the ghost domain window by up to one cached TTL configured value for A/AAAA glue records. Similar to other 'ghost domain names' attacks, an adversary needs to control a (ghost) zone and be able to query a vulnerable Unbound. A single client A/AAAA query can cause Unbound to overwrite the cached expired parent-side glue rrset and essentially extend the ghost domain window by up to one cached TTL configured value ('cache-max-ttl'). In configurations where 'harden-referral-path: yes' is used (non-default configuration), no client query is required since Unbound implicitly performs that query. This is a variant of CVE-2026-40622 which only addressed the NS query.

## Affected Products

- NLnet Labs — Unbound (1.16.2)

## References

- [CNA](https://www.nlnetlabs.nl/downloads/unbound/CVE-2026-42955.txt)

## Exploitation Prediction (EPSS)

- **EPSS Score:** 0.20%
- **EPSS Percentile:** 9.4

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_Exported from OnDuty AI Vulnerability Intelligence on 2026-09-10._