CVE-2026-34840: OneUptime SSO: Multi-Assertion Identity Injection via Decoupled Signature Verification
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.
Affected Software
Remediation
Recommended actions to resolve this vulnerability, in priority order.
- Upgrade
Upgrade
OneUptime SSO (SAML) - App/FeatureSet/Identity/Utils/SSO.tsto a version that resolves this vulnerability.Fixed in 10.0.42
Event History
Frequently Asked Questions
What is the severity of CVE-2026-34840?
CVE-2026-34840 has a medium severity rating due to its potential for multi-assertion identity injection.
How do I fix CVE-2026-34840?
To fix CVE-2026-34840, upgrade OneUptime to version 10.0.42 or later.
What software is affected by CVE-2026-34840?
CVE-2026-34840 affects OneUptime versions prior to 10.0.42.
What kind of vulnerability is CVE-2026-34840?
CVE-2026-34840 is categorized as a Multi-Assertion Identity Injection vulnerability.
Where can I find more information about CVE-2026-34840?
Details about CVE-2026-34840 can be reviewed in the security advisories and official GitHub repository from OneUptime.