# CVE-2026-32934: CoreDNS DNS-over-QUIC unbounded goroutine growth leads to denial of service > Remote attackers can cause memory exhaustion and service outage in CoreDNS by exploiting unbounded goroutine growth in the DNS-over-QUIC server. - **Severity:** High 8.7 (`CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N`) - **Exploited in the wild:** Not known - **Login needed:** Not needed - **Attackable:** Over the internet - **Victim action needed:** Not needed - **Fix available:** Yes - **Published:** 5 May 2026 - **Updated:** 6 May 2026 - **Also known as:** AZL-85728, CLEANSTART-2026-JU13039, CLEANSTART-2026-UC10506, ECHO-41d8-a79c-3211, GHSA-2wpx-qpw2-g5h5, GO-2026-4969, MINI-25r8-2mc7-g5jj, MINI-2hx6-xq7m-v2fv, MINI-4rqg-mfvh-5x2q, MINI-699p-c6vf-qqgm, MINI-73rg-wwgc-q4gq, MINI-7jvx-9x2h-692j, MINI-88h7-qxmj-6f4f, MINI-f8v4-297c-g57h, MINI-hjgg-vm48-26m7, MINI-jmg2-rwgc-v89c, MINI-m2p8-3xj4-qvr3, MINI-mmhp-7jph-rpcv, MINI-p2gq-898m-65fw, MINI-pmwq-gcj2-6r95, MINI-q353-mjxm-76wc, MINI-qf6w-2xp8-r5w2, MINI-qfvw-gqg6-w74j, MINI-vg9q-wjr4-px9f, MINI-w3j4-2398-92xw, MINI-wj6f-w6jc-xc54 ## What is CVE-2026-32934? CVE-2026-32934 is a high-severity denial of service vulnerability in coredns, published on 5 May 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 that chains plugins. In versions prior to 1.14.3, the DNS-over-QUIC (DoQ) server can be driven into unbounded goroutine and memory growth by a remote client that opens many QUIC streams and sends only 1 byte per stream. When the worker pool is full, CoreDNS still spawns a goroutine per accepted stream to wait for a worker token. Additionally, active workers block indefinitely in io.ReadFull() with no per-stream read deadline, allowing an attacker to pin all workers by sending a single byte so the read blocks waiting for the second byte of the DoQ length prefix. This enables an unauthenticated remote attacker to cause memory exhaustion and OOM-kill. This issue has been fixed in version 1.14.3. No known workarounds exist. Weakness: CWE-770 (Allocation of Resources Without Limits or Throttling) ## Which versions are affected by CVE-2026-32934? 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 | 1.14.3 | | `github.com/coredns/coredns` | Go | All versions | 1.14.3 | | `github.com/coredns/coredns` | Go | All versions | 1.14.3 | Products: Coredns.io Coredns. ## How do I fix CVE-2026-32934? Upgrade github.com/coredns/coredns to 1.14.3 or later. ## Is CVE-2026-32934 being exploited? It is not confirmed as exploited in the wild, but public exploit code for CVE-2026-32934 exists. ## Other vulnerabilities in coredns - [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) - [CVE-2026-26017](https://insights.sbomify.com/CVE-2026-26017/): CoreDNS ACL Bypass (high 7.7) ## Fix prompt for AI coding agents ```text Check this codebase for CVE-2026-32934 and fix it if it is affected. What it is: CVE-2026-32934 is a high-severity denial of service vulnerability in coredns, published on 5 May 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-2026-32934 exists. Affected packages and fixed versions: - github.com/coredns/coredns (Go): affected all versions; fixed in 1.14.3 - github.com/coredns/coredns (Go): affected all versions; fixed in 1.14.3 - github.com/coredns/coredns (Go): affected all versions; fixed in 1.14.3 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-2026-32934/ (Markdown: https://insights.sbomify.com/CVE-2026-32934/index.md) ``` ## Sources - CVE record: https://www.cve.org/CVERecord?id=CVE-2026-32934 - NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-32934 - OSV: https://osv.dev/vulnerability/CVE-2026-32934 --- From sbomify Insights: https://insights.sbomify.com/CVE-2026-32934/ Summaries are generated and may contain mistakes; the official description above is the record.