# CVE-2026-62299: Null dereference in coredns

> Remote attackers can crash CoreDNS or cause service degradation by triggering a nil-pointer panic in the rewrite plugin when specific EDNS0 revert rules are configured.

- **Severity:** Medium 5.3 (`CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:L`)
- **Exploited in the wild:** Not known
- **Login needed:** Not needed
- **Attackable:** Over the internet
- **Victim action needed:** Not needed
- **Fix available:** Yes
- **Published:** 16 Jul 2026
- **Updated:** 17 Jul 2026
- **Also known as:** AZL-92441, GHSA-9pmm-cxww-rrr7

## What is CVE-2026-62299?

CVE-2026-62299 is a medium-severity vulnerability in coredns, published on 16 Jul 2026. An attacker can exploit it over the internet without logging in, with no action from the victim.

### Official description

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.

Weakness: CWE-476 (NULL Pointer Dereference)

## Which versions are affected by CVE-2026-62299?

It affects 1 product.


Products: Coredns.io Coredns.

## How do I fix CVE-2026-62299?

Upgrade to a fixed version.

## Is CVE-2026-62299 being exploited?

It is not confirmed as exploited in the wild, but public exploit code for CVE-2026-62299 exists.

## Other vulnerabilities in coredns

- [CVE-2026-32934](https://insights.sbomify.com/CVE-2026-32934/): CoreDNS DNS-over-QUIC unbounded goroutine growth leads to denial of service (high 8.7)
- [CVE-2026-32936](https://insights.sbomify.com/CVE-2026-32936/): CoreDNS DoH GET path missing size validation causes CPU and memory amplification (high 8.7)
- [CVE-2026-33190](https://insights.sbomify.com/CVE-2026-33190/): CoreDNS TSIG authentication bypass on encrypted DNS transports (high 8.7)
- [CVE-2026-33489](https://insights.sbomify.com/CVE-2026-33489/): CoreDNS transfer plugin subzone ACL bypass via lexicographic zone comparison (high 8.2)
- [CVE-2026-35579](https://insights.sbomify.com/CVE-2026-35579/): CoreDNS TSIG authentication bypass on gRPC, QUIC, DoH, and DoH3 transports (high 8.2)

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2026-62299 and fix it if it is affected.

What it is: CVE-2026-62299 is a medium-severity vulnerability in coredns, published on 16 Jul 2026. An attacker can exploit it over the internet without logging in, with no action from the victim.
Exploitation: It is not confirmed as exploited in the wild, but public exploit code for CVE-2026-62299 exists.

Affected product: coredns. No package-level version data is available, so check the vendor advisory linked from the reference page.

Task:
1. Search the dependency manifests and lockfiles (for example package.json, package-lock.json, requirements.txt, poetry.lock, uv.lock, pom.xml, build.gradle, go.mod, Cargo.lock, Gemfile.lock) and any Dockerfiles for the affected packages, including transitive dependencies.
2. If an affected version is in use, upgrade it to the fixed version for its release line with the project's package manager, so the lockfile is regenerated. Prefer the smallest upgrade that fixes it.
3. If there is no fix, or the upgrade would break the build, do not guess: explain the risk and the safest workaround instead.
4. Run the tests and summarise what changed and why.
5. If nothing in the project is affected, say so and change nothing.

Reference: https://insights.sbomify.com/CVE-2026-62299/ (Markdown: https://insights.sbomify.com/CVE-2026-62299/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-62299
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-62299
- OSV: https://osv.dev/vulnerability/CVE-2026-62299

---
From sbomify Insights: https://insights.sbomify.com/CVE-2026-62299/
Summaries are generated and may contain mistakes; the official description above is the record.