CVE-2026-35501Bypass of a configured island trust anchor underneath an insecure parent from an atacker-controlled NSEC record.
Updated under an hour ago ()
Does this affect you?
It affects NLnet Labs Unbound. Add what you run to find out whether that includes you.
No exploitation reported and no EPSS estimate yet.
Do this next
Free account, 1 product
When NLnet Labs Unbound 1.0.1 up to and including version 1.26.1 is configured with both a root trust anchor and an additional 'trust-anchor:' for an island-of-security zone whose parent is provably insecure under the root chain, a malicious actor with a forged NSEC reply with the SOA bit cleared can trick Unbound to treat the configured trust island as insecure. This happens because the DNSSEC validator in Unbound accepts and caches the NSEC insecure response bypassing the RRSIG validation that the validator was supposed to do. The acceptance of the NSEC record at the trust anchor apex was allowed due to and old fix for type DS and NSEC queries from clients when trust anchor for that name existed.
- CVSS
- 3.7 LOW (v3.1, CNA)CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:L/A:N
- Weakness (CWE)
- CWE-354
- Known exploited
- Not in CISA's KEV catalog
- EPSS (exploitation in the next 30 days)
- Not loaded for this CVE
- Assigned by
- NLnet Labs
- NVD analysis
- Awaiting Analysis
- Record last updated
- Oct 21, 2026
- First seen by InfoSec Signals
- Oct 21, 2026
Affected products
NLnet Labs Unbound nlnet_labs:unbound (from the name) | from 1.0.1 before 1.26.2 | CNA record |
References
- https://www.nlnetlabs.nl/downloads/unbound/CVE-2026-35501.txtvendor-advisory
The CVE record on cve.org NVD's entry
The CVE record is authoritative. Products marked “from the name” were identified from the CNA's free-text names, not a CPE, and are matched less certainly. This product uses the NVD API but is not endorsed or certified by the NVD.