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CVE-2026-45674VulnerabilityPublished Updated

Io.netty:netty resolver dns: Netty Vulnerable to DNS Cache Poisoning via Missing Bailiwick Checks in CNAME Records

Affects io.netty:netty-resolver-dnsSource GCVE Database

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Not known to be exploited · CVSS 8.7 High : upgrade to 4.2.15.Final soon.

Data as of 29 Oct 2026, 19:04 UTC

CVSS 3.1 base score
8.7High
How severe the flaw is on the 0–10 CVSS scale.
EPSS
0.2% chance of exploitation in 30 days – higher than 21% of CVEsExploit Prediction Scoring System: the likelihood attackers will use this flaw soon.
Patch
Available – fixed in 4.2.15.Final, 4.1.135.Final
CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:C/C:H/I:H/A:N

Exploitation evidence

  1. Disclosed: evidence found.

    CVE published 8 Jun 2026

  2. Detectable: no evidence on record.

    No public nuclei template indexed

  3. Weaponized: evidence found.

    Public exploit code: GitHub proofs of concept

  4. Exploited in the wild: no evidence on record.

    Not in CISA KEV and no source reports exploitation

  5. Observed by OffSeq Mirage: no evidence on record.

    No attack traffic recorded by OffSeq Mirage sensors

A missing step is not evidence of safety. Sources: cve.org (opens in a new tab), GitHub proofs of concept, the Metasploit, Exploit-DB and nuclei-templates index as of 29 Oct 2026.

What to do

Description

### Summary Netty's DnsResolveContext fails to validate the origin (bailiwick) of CNAME records in DNS responses. ### Details In `io.netty.resolver.dns.DnsResolveContext#buildAliasMap`, the resolver processes the ANSWER section of a DNS response and blindly caches all CNAME records it finds. According to https://datatracker.ietf.org/doc/html/rfc5452#section-6 ``` Care must be taken to only accept data if it is known that the originator is authoritative for the QNAME or a parent of the QNAME. One very simple way to achieve this is to only accept data if it is part of the domain for which the query was intended. ``` ### Impact DNS Cache Poisoning (Bailiwick Bypass). Any application using Netty's DNS resolver is impacted.

References

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