CVE-2026-62299CWE-476

CoreDNS: rewrite-plugin EDNS0 response-revert nil-pointer panic (remote DoS) when a downstream plugin returns a response with no OPT record

Medium · published July 16, 2026

CVSS v3.1
5.3
EPSS
1%
Percentile
44.5
In the wild
Unconfirmed
What it is

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.

The record
Technical detail
CVSS v3.1
5.3 · MEDIUM
Vector
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:L
CVSS v4.0
Not supplied
EPSS
0.00538 · 44.5th percentile
Weakness
CWE-476 · NULL Pointer Dereference
Published
2026-07-16T19:44Z
EPSS history
Timeline
  • 16 JUL 19:44Z
    CoreDNS: rewrite-plugin EDNS0 response-revert nil-pointer panic (remote DoS) when a downstream plugin returns a response with no OPT record
    cvelistv5