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…
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.
Read at NIST National Vulnerability Database (CVE API 2.0)
- Vendor
- Canonical
- Product
- canonical
- CVSS
- 7.5
- EPSS
- 0.005 (p42)
- Exposure class
- Edge / VPN / firewall
Why it ranks 28 (Notable)
- CVSS 7.5 high
- Exposed product class: edge / VPN / firewall
- Covered by 2 independent sources
- Recency: items published within 24 hours gain 15, within 72 hours 6, within 7 days 2.
Links
- NIST National Vulnerability Database (CVE API 2.0) (nvd.nist.gov)
- CVE-2026-81634 on this site · NVD · CVE.org · Vulnpedia
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