# CVE-2026-26017: CoreDNS ACL Bypass > Attackers can bypass DNS access controls in CoreDNS due to a plugin execution order flaw, allowing unauthorized access. - **Severity:** High 7.7 (`CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:C/C:H/I:N/A:N`) - **Exploited in the wild:** Not known - **Login needed:** Any signed-in user - **Attackable:** Over the internet - **Victim action needed:** Not needed - **Fix available:** Yes - **Published:** 6 Mar 2026 - **Updated:** 15 Jul 2026 - **Also known as:** AZL-79497, AZL-79526, CLEANSTART-2026-RE30293, CLEANSTART-2026-TH82276, ECHO-6ae4-bee1-928d, GHSA-c9v3-4pv7-87pr, GO-2026-4630, MINI-26c6-mh7m-x477, MINI-2q63-7qjf-3v4p, MINI-2vwm-2w97-qp79, MINI-3c33-qc5p-v2mf, MINI-5fr2-76pj-83jr, MINI-7hmv-fp4r-8533, MINI-83hr-936x-fvw6, MINI-8p5j-wj26-hjjf, MINI-cv9c-829h-qvm6, MINI-g8w5-6pp8-92g4, MINI-h949-xcp3-9fwh, MINI-hhp6-3ww5-w473, MINI-m5mx-xj2q-r734, MINI-mh9q-4ppv-f334, MINI-mjp2-mxh7-g7xc, MINI-mxwf-6h9v-xxpc, MINI-p93j-j8w5-8699, MINI-pvp9-hvq7-gqv8, MINI-w349-8q8x-c8hw, MINI-wgx9-g72g-57w7, OESA-2026-2939 ## What is CVE-2026-26017? CVE-2026-26017 is a high-severity vulnerability in coredns, published on 6 Mar 2026. Any signed-in user can exploit it over the network, with no action from the victim. ### Official description 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. Weakness: CWE-367 (Time-of-check Time-of-use (TOCTOU) Race Condition) ## Which versions are affected by CVE-2026-26017? 3 open source packages ship an affected version, including github.com/coredns/coredns. It affects 1 product. | Package | Ecosystem | Affected | Fixed in | | --- | --- | --- | --- | | `github.com/coredns/coredns` | Go | All versions | 1.14.2 | | `github.com/coredns/coredns` | Go | All versions | 1.14.2 | | `github.com/coredns/coredns` | Go | All versions | 1.14.2 | Products: Coredns.io Coredns. ## How do I fix CVE-2026-26017? Upgrade github.com/coredns/coredns to 1.14.2 or later. ## Is CVE-2026-26017 being exploited? There is no known exploitation of CVE-2026-26017 in the wild and no public exploit code. ## 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-2026-26017 and fix it if it is affected. What it is: CVE-2026-26017 is a high-severity vulnerability in coredns, published on 6 Mar 2026. Any signed-in user can exploit it over the network, with no action from the victim. Exploitation: There is no known exploitation of CVE-2026-26017 in the wild and no public exploit code. Affected packages and fixed versions: - github.com/coredns/coredns (Go): affected all versions; fixed in 1.14.2 - github.com/coredns/coredns (Go): affected all versions; fixed in 1.14.2 - github.com/coredns/coredns (Go): affected all versions; fixed in 1.14.2 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-2026-26017/ (Markdown: https://insights.sbomify.com/CVE-2026-26017/index.md) ``` ## Sources - CVE record: https://www.cve.org/CVERecord?id=CVE-2026-26017 - NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-26017 - OSV: https://osv.dev/vulnerability/CVE-2026-26017 --- From sbomify Insights: https://insights.sbomify.com/CVE-2026-26017/ Summaries are generated and may contain mistakes; the official description above is the record.