{"id":"CVE-2026-81516","aliases":["GHSA-67c9-f6v2-qv86"],"url":"https://o3.security/vulnerability/CVE-2026-81516","summary":"Steeltoe.Discovery.Consul: malformed 'secure' metadata aborts service instance lookup (DoS)","details":"## Summary\n\nSteeltoe's Consul discovery client parses the `secure` metadata field on each registered service instance using `bool.Parse`, which throws on any value other than `true` or `false`. A single service instance registered with a malformed `secure` value (for example `yes` or `1`) aborts construction of the entire instance list for that service, making the service undiscoverable. When `GetAllInstancesAsync` is used, one malformed instance in any service can abort enumeration across all services.\nThis is the same \"one malformed field aborts the whole batch\" availability class as [CVE-2026-50196](https://github.com/advisories/GHSA-j8ph-6fxj-g533), but affecting the Consul discovery client.\n\n## Impact\n\nAny principal that can register a service in the Consul catalog can trigger a service-discovery outage for all Steeltoe applications resolving that service. The outage affects all instances of the targeted service — not just the malformed one — and persists until the offending registration is removed.\n\n## Affected configuration\n\n- Application uses `ConsulDiscoveryClient` (any deployment).\n- The Consul catalog contains at least one service instance with a `secure` metadata value that is not `true` or `false`.\n- Mixed-platform environments where non-.NET clients register services with non-standard metadata values are more likely to encounter this condition.\n\n## Mitigations\n\nIf an immediate upgrade is not possible:\n\n- Audit the Consul catalog for service registrations with non-standard `secure` metadata values.\n- Restrict write access to the Consul service registration API to trusted services.","published":"2026-09-17T15:38:09.014Z","modified":"2026-10-28T02:31:04.948316128Z","cvss":{"score":7.5,"severity":"HIGH","vector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H"},"epss":null,"cisaKev":null,"exploitsKnown":null,"affectedPackages":[{"ecosystem":"NuGet","name":"Steeltoe.Discovery.Consul","fixedVersion":"4.3.0"}],"fix":{"url":"https://github.com/SteeltoeOSS/Steeltoe/commit/028569c4f4f0e9e393e3c22a4fa5d07987dd8673","label":"SteeltoeOSS/Steeltoe@028569c"},"references":[{"type":"WEB","url":"https://github.com/SteeltoeOSS/Steeltoe/releases/tag/4.3.0"},{"type":"ADVISORY","url":"https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/81xxx/CVE-2026-81516.json"},{"type":"ADVISORY","url":"https://github.com/SteeltoeOSS/security-advisories/security/advisories/GHSA-67c9-f6v2-qv86"},{"type":"ADVISORY","url":"https://nvd.nist.gov/vuln/detail/CVE-2026-81516"},{"type":"FIX","url":"https://github.com/SteeltoeOSS/Steeltoe/commit/028569c4f4f0e9e393e3c22a4fa5d07987dd8673"},{"type":"PACKAGE","url":"https://github.com/SteeltoeOSS/security-advisories"}],"provenance":{"sources":["OSV.dev","FIRST.org (EPSS)"],"lastVerified":"2026-10-28T02:31:04.948316128Z"}}