CVE-2026-26017

Summary

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.

Affected Software

Weaknesses

• CWE-367: CWE-367: Time-of-check Time-of-use (TOCTOU) Race Condition

ADP Enrichment

CISA ADP Vulnrichment

• SSVC:
• Exploitation: none
  • Automatable: no
  • Technical Impact: partial

github.com/coredns/coredns: CoreDNS: DNS access control bypass due to plugin execution order flaw

Additional References

• https://access.redhat.com/security/cve/CVE-2026-26017
• https://bugzilla.redhat.com/show_bug.cgi?id=2445244
• https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-26017.json
• https://access.redhat.com/errata/RHSA-2026:25127
• https://access.redhat.com/errata/RHSA-2026:8151

References

• https://github.com/coredns/coredns/security/advisories/GHSA-c9v3-4pv7-87pr
• https://github.com/coredns/coredns/releases/tag/v1.14.2

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