{"cve":"CVE-2026-35579","nvd":{"published":"2026-05-05T21:16:22.247","modified":"2026-07-24T21:10:00.143","status":"Modified","description":"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.\n\nAn 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.\n\nThis 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.","cvss_v4":{"vector":"CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:N/VC:H/VI:N/VA:N/SC:N/SI:N/SA:N","score":8.2},"cvss_v3":{"version":"3.1","vector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H","score":9.8},"cwes":["CWE-287","CWE-303"],"references":["https://github.com/coredns/coredns/security/advisories/GHSA-vp29-5652-4fw9","https://access.redhat.com/errata/RHSA-2026:25127","https://access.redhat.com/security/cve/CVE-2026-35579","https://bugzilla.redhat.com/show_bug.cgi?id=2466905","https://github.com/coredns/coredns/security/advisories/GHSA-vp29-5652-4fw9"],"products":["coredns.io:coredns"],"source":"nvd","synced_at":"2026-10-19T22:33:55.586217763+00:00"},"epss":{"cve":"CVE-2026-35579","score":0.00611,"percentile":0.49244,"date":"2026-10-31"},"kev":null,"osv":[{"id":"GHSA-vp29-5652-4fw9","url":"https://osv.dev/vulnerability/GHSA-vp29-5652-4fw9","summary":"CoreDNS has TSIG authentication bypass on gRPC and QUIC transports","modified":"2026-09-10T03:51:03.373518238Z","packages":[{"ecosystem":"Go","name":"github.com/coredns/coredns","purl":"pkg:golang/github.com/coredns/coredns","ranges":["<1.14.3"],"fixed":["1.14.3"]}]},{"id":"GO-2026-5667","url":"https://osv.dev/vulnerability/GO-2026-5667","summary":"CoreDNS has TSIG authentication bypass on gRPC and QUIC transports in github.com/coredns/coredns","modified":"2026-06-25T23:01:27.986031503Z","packages":[{"ecosystem":"Go","name":"github.com/coredns/coredns","purl":"pkg:golang/github.com/coredns/coredns","ranges":["<1.14.3"],"fixed":["1.14.3"]}]}],"attribution":["This product uses the NVD API but is not endorsed or certified by the NVD.","EPSS scores: FIRST Exploit Prediction Scoring System, https://www.first.org/epss","Known exploited vulnerabilities: CISA Known Exploited Vulnerabilities Catalog, https://www.cisa.gov/known-exploited-vulnerabilities-catalog","Package advisories: OSV (https://osv.dev), from the GitHub Advisory Database, PyPA, Go, RustSec and other ecosystem databases, under CC-BY 4.0 or CC0","CVE records: the CVE Program's CVE List (https://www.cve.org), under its terms of use (https://www.cve.org/Legal/TermsOfUse). CVE is a registered trademark of The MITRE Corporation; this product is not affiliated with the CVE Program."]}