CVE-2026-81634
Last modified
CVE-2026-81634 is a high-severity vulnerability rated 7.5/10 on the CVSS scale. 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. EPSS estimates a 0.36% chance of exploitation in the next 30 days.
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.
Metrics
Weakness Enumeration
Affected Software
Source: CNA advisory (CVE.org). NVD analysis pending.
| Vendor | Product | Versions |
|---|---|---|
| NLnet Labs | Unbound | < 1.26.1 |
References
Timeline
- Published
- Last Modified
- Status
- Awaiting Analysis
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