{"id":"CVE-2026-34840","aliases":["EUVD-2026-18533","GHSA-5w5c-766x-265g"],"status":"published","title":"OneUptime SSO: Multi-Assertion Identity Injection via Decoupled Signature Verification","description":"OneUptime is an open-source monitoring and observability platform. Prior to version 10.0.42, OneUptime's SAML SSO implementation (App/FeatureSet/Identity/Utils/SSO.ts) has decoupled signature verification and identity extraction. isSignatureValid() verifies the first \u003cSignature\u003e element in the XML DOM using xml-crypto, while getEmail() always reads from assertion[0] via xml2js. An attacker can prepend an unsigned assertion containing an arbitrary identity before a legitimately signed assertion, resulting in authentication bypass. This issue has been patched in version 10.0.42.","severity":{"version":"3.1","score":8.1,"vector":"CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:N","level":"high","assessor":"cna","from":"cve"},"epss":{"day":"2026-11-09","score":0.00269,"percentile":0.19161,"model":"v2026.06.15"},"facts":{"in_kev":false,"known_exploited":false,"public_exploit":false,"fix_available":false},"cwes":["CWE-347"],"published":"2026-04-02T18:52:48Z","modified":"2026-10-28T02:31:07Z","products":[{"vendor":"hackerbay","product":"oneuptime"},{"vendor":"oneuptime","product":"oneuptime"}],"references":[{"url":"https://github.com/OneUptime/oneuptime/security/advisories/GHSA-5w5c-766x-265g","tags":["x_refsource_CONFIRM","Exploit","Mitigation","Vendor Advisory","advisory"]},{"url":"https://github.com/OneUptime/oneuptime/commit/2fd7ede52f60444710628d6c1b34dee2ef9e57d1","tags":["x_refsource_MISC","Patch","fix"]},{"url":"https://github.com/OneUptime/oneuptime/releases/tag/10.0.42","tags":["x_refsource_MISC","Product","Release Notes","web"]},{"url":"https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/34xxx/CVE-2026-34840.json","tags":["advisory"]},{"url":"https://nvd.nist.gov/vuln/detail/CVE-2026-34840","tags":["advisory"]}],"sources":{"cve":[{"id":"CVE-2026-34840","title":"OneUptime SSO: Multi-Assertion Identity Injection via Decoupled Signature Verification","description":"OneUptime is an open-source monitoring and observability platform. Prior to version 10.0.42, OneUptime's SAML SSO implementation (App/FeatureSet/Identity/Utils/SSO.ts) has decoupled signature verification and identity extraction. isSignatureValid() verifies the first \u003cSignature\u003e element in the XML DOM using xml-crypto, while getEmail() always reads from assertion[0] via xml2js. An attacker can prepend an unsigned assertion containing an arbitrary identity before a legitimately signed assertion, resulting in authentication bypass. This issue has been patched in version 10.0.42.","status":"published","published":"2026-04-02T18:52:48.274Z","modified":"2026-04-02T20:20:13.291Z","cvss":[{"version":"3.1","score":8.1,"vector":"CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:N","level":"high","assessor":"cna"}],"cwes":["CWE-347"],"updated_at":"2026-11-02T14:20:13.962274Z"}],"euvd":[{"id":"EUVD-2026-18533","description":"OneUptime is an open-source monitoring and observability platform. Prior to version 10.0.42, OneUptime's SAML SSO implementation (App/FeatureSet/Identity/Utils/SSO.ts) has decoupled signature verification and identity extraction. isSignatureValid() verifies the first \u003cSignature\u003e element in the XML DOM using xml-crypto, while getEmail() always reads from assertion[0] via xml2js. An attacker can prepend an unsigned assertion containing an arbitrary identity before a legitimately signed assertion, resulting in authentication bypass. This issue has been patched in version 10.0.42.","status":"published","published":"2026-04-02T18:52:48Z","modified":"2026-04-02T20:20:13Z","cvss":[{"version":"3.1","score":8.1,"vector":"CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:N","level":"high"}],"updated_at":"2026-11-02T19:25:17.32175Z"}],"nvd":[{"id":"CVE-2026-34840","description":"OneUptime is an open-source monitoring and observability platform. Prior to version 10.0.42, OneUptime's SAML SSO implementation (App/FeatureSet/Identity/Utils/SSO.ts) has decoupled signature verification and identity extraction. isSignatureValid() verifies the first \u003cSignature\u003e element in the XML DOM using xml-crypto, while getEmail() always reads from assertion[0] via xml2js. An attacker can prepend an unsigned assertion containing an arbitrary identity before a legitimately signed assertion, resulting in authentication bypass. This issue has been patched in version 10.0.42.","status":"published","published":"2026-04-02T20:16:28.357Z","modified":"2026-10-06T22:10:00.247Z","cvss":[{"version":"3.1","score":8.1,"vector":"CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:N","level":"high","assessor":"secondary"}],"cwes":["CWE-347"],"updated_at":"2026-11-02T14:12:12.73929Z"}],"osv":[{"id":"CVE-2026-34840","title":"OneUptime SSO: Multi-Assertion Identity Injection via Decoupled Signature Verification","description":"OneUptime is an open-source monitoring and observability platform. Prior to version 10.0.42, OneUptime's SAML SSO implementation (App/FeatureSet/Identity/Utils/SSO.ts) has decoupled signature verification and identity extraction. isSignatureValid() verifies the first \u003cSignature\u003e element in the XML DOM using xml-crypto, while getEmail() always reads from assertion[0] via xml2js. An attacker can prepend an unsigned assertion containing an arbitrary identity before a legitimately signed assertion, resulting in authentication bypass. This issue has been patched in version 10.0.42.","status":"published","published":"2026-04-02T18:52:48.274Z","modified":"2026-10-28T02:31:07.944183455Z","cvss":[{"version":"3.1","score":8.1,"vector":"CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:N","level":"high"}],"cwes":["CWE-347"],"updated_at":"2026-11-02T15:45:02.673625Z"}]}}