Vulnerability · Published May 5, 2026 · Assigned by GitHub_M

CVE-2026-33489CoreDNS transfer plugin subzone ACL bypass via lexicographic zone comparison

High 8.2

In plain English

A high-severity incorrect authorization in coredns from coredns. Proof-of-concept exploit code is public. The chance it is exploited in the next 30 days is estimated at 0.4% (higher than 35% of all known vulnerabilities). Fixed versions are available - upgrade the affected package.

Severity (CVSS 4.0)8.2High

Exploit odds (30 days)0.4%top 65.1% of all CVEs

Exploited in the wildNo reportsCISA SSVC: poc

Attack toolingNoneno public tooling known

Official description

CoreDNS is a DNS server that chains plugins. In versions prior to 1.14.3, the transfer plugin can select the wrong ACL stanza when both a parent zone and a more-specific subzone are configured. The longestMatch() function in plugin/transfer/transfer.go uses a lexicographic string comparison instead of an actual longest-suffix match to select the winning zone. As a result, a permissive parent-zone transfer rule can override a restrictive subzone rule depending on zone name ordering (e.g., "example.org." > "a.example.org." lexicographically). This allows an unauthorized remote client to perform AXFR/IXFR for the subzone and retrieve its full zone contents. This issue has been fixed in version 1.14.3.

Affected packages & fixed versions

Ecosystem	Package	Fixed in	Advisory
Go	github.com/coredns/coredns	1.14.3	GHSA-h8mm-c463-wjq3
Go	github.com/coredns/coredns	1.14.3	GO-2026-5417

Affected products (as reported)

Vendor	Product	Versions
coredns	coredns	< 1.14.3

Weakness: CWE-863 · Vector: CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:N/VC:H/VI:N/VA:N/SC:N/SI:N/SA:N

References

https://github.com/coredns/coredns/security/advisories/GHSA-h8mm-c463-wjq3 x_refsource_CONFIRM
https://github.com/coredns/coredns/releases/tag/v1.14.3 x_refsource_MISC