In NLnet Labs Unbound 1.13.2 up to and including 1.26.1, a vulnerability in ZONEMD configured zones (zonemd-check
Affects unboundSource GCVE Database
Not known to be exploited · CVSS 4.4 Medium.
Data as of 7 Nov 2026, 23:24 UTC
- EPSS
- 0.1% chance of exploitation in 30 days – higher than 6% of CVEsExploit Prediction Scoring System: the likelihood attackers will use this flaw soon.
CVSS:3.1/AV:N/AC:H/PR:H/UI:N/S:U/C:N/I:H/A:NExploitation evidence
Disclosed: evidence found.
CVE published 16 Sep 2026
Detectable: no evidence on record.
No public nuclei template indexed
Weaponized: no evidence on record.
No public exploit code indexed in Metasploit or Exploit-DB
Exploited in the wildExploited: no evidence on record.
Not in CISA KEV and no source reports exploitation
Observed by OffSeq MirageSeen by Mirage: no evidence on record.
No attack traffic recorded by OffSeq Mirage sensors
A missing step is not evidence of safety. Sources: cve.org (opens in a new tab), the Metasploit, Exploit-DB and nuclei-templates index as of 8 Nov 2026.
What to do
Affected software
| Product | Affected | Fixed in |
|---|---|---|
Ubuntu 26.10unboundpkg:deb/ubuntu/unbound?arch=source&distro=stonkingOther threats | Affected
| Fixed in– |
Ubuntu 26.04 LTSunboundpkg:deb/ubuntu/unbound?arch=source&distro=resoluteOther threats | Affected
| Fixed in– |
Ubuntu 24.04 LTSunboundpkg:deb/ubuntu/unbound?arch=source&distro=nobleOther threats | Affected
| Fixed in– |
Ubuntu 22.04 LTSunboundpkg:deb/ubuntu/unbound?arch=source&distro=jammyOther threats | Affected
| Fixed in– |
Ubuntu Pro 20.04 LTSunboundpkg:deb/ubuntu/unbound?arch=source&distro=esm-infra/focalOther threats | Affected
| Fixed in– |
Ubuntu Pro 18.04 LTSunboundpkg:deb/ubuntu/unbound?arch=source&distro=esm-infra/bionicOther threats | Affected
| Fixed in– |
Check your own hosts for these packages with threat-finder (opens in a new tab), our free open-source scanner.
AI-suggested
Until a fix is available, administrators should be aware of the risk of tampered zone data persisting on disk and consider monitoring or manual intervention to discard corrupted data if detected.
Description
NLnet Labs Unbound versions 1.13.2 through 1.26.1 have a vulnerability affecting zones configured with ZONEMD (zonemd-check: yes) located below a trust anchor. Due to asynchronous DS/DNSKEY resolution before ZONEMD integrity checks complete, tampered zone contents may be temporarily served or stored on disk. If tampered data is written and the ZONEMD check fails, corrupted data persists on disk and is reloaded on startup until verification succeeds or data is discarded.