CVE-2026-34840 (GCVE-0-2026-34840)
Vulnerability from cvelistv5 – Published: 2026-04-02 18:52 – Updated: 2026-04-02 20:20
VLAI
EPSS
VEX
Title
OneUptime SSO: Multi-Assertion Identity Injection via Decoupled Signature Verification
Summary
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 <Signature> 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
8.1 (High)
SSVC
Exploitation: poc
Automatable: no
Technical Impact: total
CISA Coordinator · CISA-ADP (v2.0.3)
Decision recorded 2026-04-02 20:20 UTC
CWE
- CWE-347 - Improper Verification of Cryptographic Signature
Assigner
References
3 references
| URL | Tags |
|---|---|
| https://github.com/OneUptime/oneuptime/security/a… | x_refsource_CONFIRM |
| https://github.com/OneUptime/oneuptime/commit/2fd… | x_refsource_MISC |
| https://github.com/OneUptime/oneuptime/releases/t… | x_refsource_MISC |
Impacted products
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