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7.5 High

CVE-2026-81634 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…

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.

Affected products and versions

Product Affected versions Fixed in
unbound 1.26 earliest → < 1.26.1 1.26.1

References

Timeline

  1. Published
  2. Last modified

Other CVEs of unbound

The 58 CVEs of unbound →
CVE-2026-97206 NLnet Labs Unbound, 1.22.0 up to and including version 1.26.1, contains a DNS-over-QUIC (DoQ) lifetime bug reachable… 7.5 High CVE-2026-96405 NLnet Labs Unbound up to and including version 1.26.1 limits compression-pointer traversal for each individual… 5.3 Medium CVE-2026-50106 When NLnet Labs Unbound up to and including version 1.26.1 is configured with both a root trust anchor and an additional… 6.5 Medium CVE-2026-35501 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… 3.7 Low
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