Possible heap buffer overflow during DNSSEC canonicalization (NLnet Labs Unbound)
At a glance
- Source
- NVD
- EPSS
- EPSS 0.48 % · percentile 41 ()
- State
- PUBLISHED
- Published
- Updated
- Assigner
- NLnet Labs
- NVD status
- Analyzed
Description
In NLnet Labs Unbound up to and including 1.26.0, a 255 length query name with a large TCP response can lead to a heap buffer overflow during the RRSet canonicalisation routine. This is caused by missing to add the first owner name into the buffer length check. A malicious actor operating a malicious name server or tampering with an incoming response to Unbound (canonicalisation happens before DNSSEC validation), can trigger the vulnerability.
Weaknesses (CWE)
- CWE-122 — Heap-based Buffer Overflow
References
Scores
| Version | Score | Vector | Scored by |
|---|---|---|---|
| CVSS 3.1 | HIGH 7.5 | CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H | NLnet Labs |
| CVSS 3.1 | HIGH 7.5 | CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H | NVD · sep@nlnetlabs.nl (Secondary) |
European references
- ENISA EUVD · EUVD-2026-80290
- GCVE · GCVE-0-2026-81634
Affected configurations (NVD CPE)
cpe:2.3:a:nlnetlabs:unbound:*:*:*:*:*:*:*:*< 1.26.1
Affected products
| Product | Versions |
|---|---|
| NLnet Labs · Unbound | affected 0 < 1.26.1 |
Sources
| Source | Licence |
|---|---|
| CVE List (CVEProject cvelistV5) | CVE Program Terms of Use |
| EPSS (FIRST.org) | FIRST — attribution requested |
| ENISA EUVD | ENISA — reproduction authorised, source acknowledged |
| NVD (NIST) via fkie-cad/nvd-json-data-feeds | Public domain — this product uses data from the NVD API but is not endorsed or certified by the NVD |