CVE-2026-33489

CVE-2026-33489 is a high-severity vulnerability in Coredns.io Coredns with a CVSS 3.x base score of 7.5. It is not currently listed as actively exploited by CISA, and its EPSS exploit-prediction score is low. The underlying weakness is classified as CWE-863.

Key facts

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.

Frequently asked questions

What is CVE-2026-33489?
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.
How severe is CVE-2026-33489?
CVE-2026-33489 has a CVSS 3.x base score of 7.5, rated high severity. It is exploitable over network with low attack complexity, requires no privileges and no user interaction. Impact on confidentiality is high, integrity none, and availability none.
Is CVE-2026-33489 being actively exploited?
It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 0% (31st percentile), an estimate of the probability of exploitation in the next 30 days.
What products are affected by CVE-2026-33489?
CVE-2026-33489 affects Coredns.io Coredns. See the affected-products list for the exact vulnerable versions.
How do I fix CVE-2026-33489?
Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround. Given its high severity, prioritise patching exposed systems.
Does CVE-2026-33489 have an EU (EUVD) identifier?
Yes. CVE-2026-33489 is tracked in the ENISA EU Vulnerability Database (EUVD) as EUVD-2026-27450.
When was CVE-2026-33489 published?
CVE-2026-33489 was published on 2026-05-05 and last updated on 2026-06-17.

References

Affected products (1)

More vulnerabilities in Coredns.io Coredns

All CVEs affecting Coredns.io Coredns →

Other CWE-863 (Incorrect Authorization) vulnerabilities

Browse all CWE-863 (Incorrect Authorization) vulnerabilities →