# CVE-2026-62299: CoreDNS NULL pointer dereference in rewrite plugin

Source: https://junglewise.ai/threats/cve-2026-62299-coredns-null-pointer-dereference-in-rewrite-plugin  
Publisher: Junglewise Threat Intelligence, https://junglewise.ai/threats  
Published: 2026-07-16. Updated: 2026-07-16  
License: CC BY 4.0 with a link back

CVE-2026-62299 · Severity: medium · CVSS 5.3 · Published 2026-07-16

CoreDNS is a popular open-source DNS server used to translate human-readable domain names into IP addresses. A flaw in its 'rewrite' plugin allows a remote attacker to send a specially crafted DNS query that causes the server to encounter an internal error. In most cases, this results in the server failing to answer the request (returning a SERVFAIL error), but if specific debugging features are enabled, it can cause the entire DNS service to crash, leading to a service outage.

Technologies: [CoreDNS](https://junglewise.ai/threats/technologies/coredns). Vendors: [CoreDNS](https://junglewise.ai/threats/vendors/coredns).

## Quick answers

**Is CVE-2026-62299 exploited in the wild?** No. Junglewise Threat Intelligence has no report of CVE-2026-62299 being exploited in the wild.

**How severe is CVE-2026-62299?** Medium severity, with a CVSS score of 5.3, published 16 July 2026.

**Which products and versions are affected?** CoreDNS < 1.14.5.

**Is there a fix for CVE-2026-62299?** A patch was published on 2026-06-23: Fix merged into master branch Junglewise finds every place you run it, drafts the upgrade and applies it once you approve.

**How is CVE-2026-62299 attacked?** It is attacked over the network, in a hosted service.

**Am I affected by CVE-2026-62299?** Check whether you run CoreDNS at an affected version. Junglewise does that check for you around the clock: connect your code, cloud and domains, and it matches new vulnerabilities like this one against what you actually run and tells you when one reaches you.

## Technical details

A NULL pointer dereference exists in the CoreDNS 'rewrite' plugin within the edns0SetResponseRule and edns0ReplaceResponseRule components. When a rewrite rule uses the 'revert' flag, the plugin attempts to restore EDNS0 options in the response; however, it fails to verify if an OPT record exists before dereferencing the pointer returned by res.IsEdns0(). An unauthenticated remote attacker can trigger this by sending a DNS query that matches a 'rewrite edns0 ... revert' rule when the downstream plugin returns a response without an OPT record (common in authoritative replies). This results in a Go panic; while usually caught by the server's recovery handler (resulting in SERVFAIL), it will crash the process if the 'debug' directive is enabled. The issue is fixed in version 1.14.5.

## Affected products

- CoreDNS CoreDNS < 1.14.5

## Timeline

- 2026-06-23: patched: Fix merged into master branch
- 2026-07-10: advisory: Version 1.14.5 released
- 2026-07-16: disclosed: CVE-2026-62299 published

## References

- [https://github.com/coredns/coredns/commit/fc447d0658b093edc8cd29a6b171216a44a644c2](https://github.com/coredns/coredns/commit/fc447d0658b093edc8cd29a6b171216a44a644c2)
- [https://github.com/coredns/coredns/pull/8190](https://github.com/coredns/coredns/pull/8190)
- [https://github.com/coredns/coredns/releases/tag/v1.14.5](https://github.com/coredns/coredns/releases/tag/v1.14.5)
- [https://github.com/coredns/coredns/security/advisories/GHSA-9pmm-cxww-rrr7](https://github.com/coredns/coredns/security/advisories/GHSA-9pmm-cxww-rrr7)

## Related threats

- [CoreDNS RFC 2136 UPDATE bypass in DoH/DoQ/gRPC](https://junglewise.ai/threats/cve-2026-86003-coredns-rfc-2136-update-bypass-in-doh-doq-grpc)
- [CoreDNS unauthenticated memory exhaustion in DoH, DoQ, and DoH3](https://junglewise.ai/threats/cve-2026-82399-coredns-unauthenticated-memory-exhaustion-in-doh-doq-and-doh3)
- [CoreDNS panic in transfer plugin via k8s_external headless services](https://junglewise.ai/threats/cve-2026-62994-coredns-panic-in-transfer-plugin-via-k8s-external-headless)
- [CoreDNS NULL pointer dereference in proxyproto plugin](https://junglewise.ai/threats/cve-2026-62309-coredns-null-pointer-dereference-in-proxyproto-plugin)
- [CoreDNS TSIG authentication bypass in gRPC, QUIC, and DoH transports](https://junglewise.ai/threats/cve-2026-35579-coredns-tsig-authentication-bypass-in-grpc-quic-and-doh)