CVE-2026-816347.5HighCWE-122
Possible heap buffer overflow during DNSSEC canonicalization
NLnet Labs · Unbound
Not in CISA KEVVendor fix available
0.5%probability of exploitation in the next 30 days
41st percentile
050100
Higher than 41% of scored CVEs
7.5HighCVSS 3.1
LowMediumHighCrit.
DescriptionNVD
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.
Coverage1 article · 1 outlet
First in our coverage: SecurityOnline, 17 Sep.
- Unbound 1.26.1 Fixes Critical DNSSEC Flaw and RCE RisksSecurityOnline · first in our coverage · mentions it in passing
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