CVE-2026-26017 CoreDNS ACL Bypass

What is CVE-2026-26017?

CVE-2026-26017 is a high-severity vulnerability in coredns, published on 6 Mar 2026. Any signed-in user can exploit it over the network, with no action from the victim.

Official description

CoreDNS is a DNS server that chains plugins. Prior to version 1.14.2, a logical vulnerability in CoreDNS allows DNS access controls to be bypassed due to the default execution order of plugins. Security plugins such as acl are evaluated before the rewrite plugin, resulting in a Time-of-Check Time-of-Use (TOCTOU) flaw. This issue has been patched in version 1.14.2.

Weakness: CWE-367

Which versions are affected by CVE-2026-26017?

3 open source packages ship an affected version, including github.com/coredns/coredns. It affects 1 product.

Products include Coredns.io Coredns.

How do I fix CVE-2026-26017?

Upgrade github.com/coredns/coredns to 1.14.2 or later.

Is CVE-2026-26017 being exploited?

There is no known exploitation of CVE-2026-26017 in the wild and no public exploit code.

Other vulnerabilities in coredns

• CVE-2026-32934 CoreDNS DNS-over-QUIC unbounded goroutine growth leads to denial of service High 8.7
• CVE-2026-32936 CoreDNS DoH GET path missing size validation causes CPU and memory amplification High 8.7
• CVE-2026-33190 CoreDNS TSIG authentication bypass on encrypted DNS transports High 8.7
• CVE-2026-33489 CoreDNS transfer plugin subzone ACL bypass via lexicographic zone comparison High 8.2
• CVE-2026-35579 CoreDNS TSIG authentication bypass on gRPC, QUIC, DoH, and DoH3 transports High 8.2

Sources

• CVE record
• NVD
• OSV
• GitHub advisory
• How this page is made

Also known as AZL-79497, AZL-79526, CLEANSTART-2026-RE30293, CLEANSTART-2026-TH82276, ECHO-6ae4-bee1-928d, GHSA-c9v3-4pv7-87pr and 22 more.