{"id":"CVE-2026-81868","summary":"Steeltoe: Header-forwarded client cert lacks proof of private-key possession","details":"Steeltoe is an open source project that provides a collection of libraries that helps users build cloud-native applications. Prior to 4.3.0, Steeltoe.Security.Authorization.Certificate deployments using AddOrgAndSpacePolicies() and UseCertificateAuthorization() trust the public certificate supplied in the X-Client-Cert request header without proving possession of the corresponding private key. Common Cloud Foundry routers do not remove this header from inbound requests. When inbound requests are not restricted to a known trusted proxy source IP, an attacker who obtains the public certificate of an application instance in the target organization or space and can reach the application can spoof X-Client-Cert to bypass the SameOrg and SameSpace policies for the certificate validity period. This issue is fixed in version 4.3.0.","aliases":["GHSA-5mq7-rwhj-4fh9"],"modified":"2026-09-19T03:47:23.607567944Z","published":"2026-09-17T15:36:23.149Z","database_specific":{"cna_assigner":"GitHub_M","cwe_ids":["CWE-288","CWE-295"],"osv_generated_from":"https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/81xxx/CVE-2026-81868.json"},"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-2026-81868.json"},{"type":"ADVISORY","url":"https://github.com/SteeltoeOSS/security-advisories/security/advisories/GHSA-5mq7-rwhj-4fh9"},{"type":"ADVISORY","url":"https://nvd.nist.gov/vuln/detail/CVE-2026-81868"},{"type":"FIX","url":"https://github.com/SteeltoeOSS/Steeltoe/commit/b626ef3d60aaf19c68eeeed5ee81045406c8c6d0"}],"affected":[{"ranges":[{"type":"GIT","repo":"https://github.com/steeltoeoss/steeltoe","events":[{"introduced":"0"},{"fixed":"b626ef3d60aaf19c68eeeed5ee81045406c8c6d0"},{"fixed":"a56a5e5a324a1581cbfcdf726dbca3e25b604f86"}],"database_specific":{"extracted_events":[{"introduced":"0"},{"fixed":"4.3.0"}],"source":["AFFECTED_FIELD","REFERENCES"]}}],"versions":["4.2.0","4.1.0","4.0.0","4.0.0-rc1","4.0.0-beta1","3.2.0","3.2.0-rc1","3.1.1","3.1.0","3.1.0-rc2","3.1.0-rc1","3.0.x_2021-Jan-12","3.0.2","3.0.1","3.0.0","3.0.0-rc1","3.0.0-m3","3.0.0-m2","3.0.0-m1"],"database_specific":{"source":"https://storage.googleapis.com/cve-osv-conversion/osv-output/CVE-2026-81868.json"}}],"schema_version":"1.9.0","severity":[{"type":"CVSS_V3","score":"CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:L/A:N"}]}