CVE-2026-62299
CoreDNS is a DNS server written in Go. Prior to 1.14.5, the CoreDNS rewrite plugin supports edns0 rewrite rules with an optional revert flag, and two response rules, edns0SetResponseRule and edns0ReplaceResponseRule[T] in plugin/rewrite/edns0.go, call res.IsEdns0() and immediately dereference the returned *dns.OPT without a nil check when a downstream plugin returns a response with no OPT record. A remote, unauthenticated client can send a single ordinary DNS query matching a rewrite edns0 <local|nsid|subnet> <set|append|replace> ... revert rule, causing ResponseReverter in plugin/rewrite/reverter.go to panic, return SERVFAIL, and degrade availability, or crash the CoreDNS process if the debug directive disables recovery. This issue is fixed in version 1.14.5.
CSIRTS triage
- What
- The rewrite-plugin can cause a nil-pointer panic when a downstream plugin returns a response without an OPT record, resulting in a denial of service.
- Who is affected
- Deployments of CoreDNS using the rewrite-plugin.
- Urgency
- Remediation is important as this vulnerability has medium severity and can lead to service disruption.
- Action
- Update to the latest version of CoreDNS that resolves this issue.
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Exploitation outlook
- Low exploitation risk0.31% 30-day exploitation probability — currently an unlikely target, but scores change as exploit code circulates. Riskier than 24% of all EPSS-scored CVEs.
Advisory coverage (2)
External references
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