CVE-2026-33489: CoreDNS incorrect authorization in transfer plugin ACL selection

CVE-2026-33489 · Severity: high · CVSS 7.5 · Published 2026-05-05

CoreDNS is a widely used DNS server that manages how domain name information is distributed. A security flaw in its zone transfer plugin allows unauthorized users to bypass security restrictions and download the entire contents of a specific domain's database (zone file). This could lead to the exposure of sensitive internal network infrastructure and private records to external attackers.

Technologies: CoreDNS, github.com/coredns/coredns (Go). Vendors: CoreDNS, Go.

Quick answers

Is CVE-2026-33489 exploited in the wild?
No. Junglewise Threat Intelligence has no report of CVE-2026-33489 being exploited in the wild.
How severe is CVE-2026-33489?
High severity, with a CVSS score of 7.5, published 5 May 2026.
Which products and versions are affected?
CoreDNS < 1.14.3; github.com/coredns/coredns (Go) SEMVER:introduced=0,fixed=1.14.3.
Is there a fix for CVE-2026-33489?
Yes. github.com/coredns/coredns (Go): upgrade to 1.14.3 or later. Junglewise finds every place you run it, drafts the upgrade and applies it once you approve.
How is CVE-2026-33489 attacked?
It is attacked over the network, in a hosted service.
Am I affected by CVE-2026-33489?
Check whether you run CoreDNS or github.com/coredns/coredns (Go) at an affected version. Junglewise does that check for you around the clock: connect your code, cloud and domains, and it matches new vulnerabilities like this one against what you actually run and tells you when one reaches you.

How to fix

  • github.com/coredns/coredns (Go): upgrade to 1.14.3 or later
    go get github.com/coredns/coredns@v1.14.3

Technical details

An authorization bypass exists in the CoreDNS 'transfer' plugin due to a logic error in the longestMatch() function within plugin/transfer/transfer.go. Instead of performing a proper longest-suffix match to identify the most specific DNS zone, the function uses a lexicographic string comparison. This allows a permissive Access Control List (ACL) defined for a parent zone (e.g., example.org) to override a more restrictive ACL for a subzone (e.g., a.example.org) if the parent zone name is lexicographically 'greater' than the subzone name. A remote, unauthenticated attacker can exploit this to perform unauthorized AXFR or IXFR requests, resulting in the full disclosure of zone data. The issue is resolved in CoreDNS version 1.14.3.

Affected products

  • CoreDNS CoreDNS < 1.14.3

Identifiers

  • CVE-2026-33489
  • GHSA-h8mm-c463-wjq3
  • GO-2026-5417

Timeline

  • 2026-04-22: patched: Version 1.14.3 released
  • 2026-04-25: advisory: GitHub Security Advisory published
  • 2026-05-05: disclosed: CVE published to NVD

References

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