GHSA-vp29-5652-4fw9 · Severity: high · Ecosystem: go — CoreDNS has TSIG authentication bypass on gRPC and QUIC transports
CoreDNS is a DNS server written in Go. In versions prior to 1.14.3, the gRPC, QUIC, DoH, and DoH3 transport implementations incorrectly handle TSIG authentication. For gRPC and QUIC, the server checks whether the TSIG key name exists in the configuration but never calls dns.TsigVerify() to validate the HMAC. If the key name matches a configured key, the tsigStatus field remains nil and the tsig plugin treats the request as successfully authenticated regardless of the MAC value. For DoH and DoH3, the issue is more severe: the DoHWriter.TsigStatus() method unconditionally returns nil, and the server never inspects the TSIG record at all. Any request containing a TSIG record is treated as authenticated over DoH and DoH3, even if the key name is invalid and the MAC is arbitrary. An unauthenticated network attacker can exploit this to bypass TSIG-protected functionality such as AXFR/IXFR zone transfers, dynamic DNS updates, or other TSIG-gated plugin behavior. The DoH and DoH3 variants have a lower exploitation bar because the attacker does not need to know a valid TSIG key name. This issue has been fixed in version 1.14.3. As a workaround, disable gRPC, QUIC, DoH, and DoH3 listeners where TSIG authentication is required, or restrict network-level access to affected transport ports to trusted sources only.
Conclusion & alert: CVE-2026-35579 is rated Exploit Available (53.7/100): CVSS High severity, with low exploitation likelihood (EPSS 0.05%). Core evidence: 1 public exploit reference(s) are indexed (Exploit-DB). Mandatory action: Public exploits are available—assess exposure, apply mitigations, and prioritize patching.
Risk is dynamic; we continuously reassess and refresh what is shown on this page as upstream context changes.
| EDB-ID | Source | Kind | Published | Link |
|---|---|---|---|---|
| — | nvd_ref | exploit_tag | Exploit-DB ↗ |
EPSS lead: Daily EPSS estimates relative likelihood of exploitation; percentile ranks this CVE among scored vulnerabilities (higher = more severe relative rank).
| # | Date | Old EPSS score | New EPSS score | Delta (New - Old) |
|---|---|---|---|---|
| 1 | 2026-05-06 | — | 0.05% | — |
Full EPSS history (1 record total)
CVSS metrics for this CVE.
| Base score | Version | Severity | Vector | Exploitability | Impact | Score source |
|---|---|---|---|---|---|---|
| 8.2 | 4.0 | HIGH |
|
— | — | [email protected] |
| 9.8 | 3.1 | CRITICAL |
|
3.9 | 5.9 | [email protected] |
GHSA-vp29-5652-4fw9 · Severity: high · Ecosystem: go — CoreDNS has TSIG authentication bypass on gRPC and QUIC transports
| Vendor | Product | Version | Raw CPE |
|---|---|---|---|
| coredns.io | coredns | < 1.14.3 | cpe:2.3:a:coredns.io:coredns:*:*:*:*:*:*:*:* |
| URL | Tags |
|---|---|
| https://github.com/coredns/coredns/security/advisories/GHSA-vp29-5652-4fw9 | Exploit Vendor Advisory Mitigation |