CVE-2026-34840
HighCVSS 8.1Exploitation Probability (EPSS)
Low risk18th percentile - higher than 18% of all known CVEs
Summary
In OneUptime prior to version 10.0.42, the SAML SSO implementation decouples signature verification from identity extraction. An attacker can prepend an unsigned assertion with an arbitrary identity before a legitimately signed one, leading to authentication bypass.
Risk Assessment
Bypassing SAML SSO authentication allows an attacker to log in as any user, including administrators, without knowing their credentials.
Recommendation
Immediately upgrade OneUptime to version 10.0.42 or later, which includes the fix.
Other vulnerabilities in OneUptime
See all- CVE-2026-80350High
OneUptime's webhook target check rejects private and loopback addresses given in IPv4 form and a small set of IPv6 forms, but has no case for the IPv4-mapped IPv6 range. The webhook delivery path calls SSRFProtection.validateWebhookTargetIsSafe, and the host-literal screening inside Common/Server/Utils/SSRFProtection.ts, performed by isBlockedHostnameLiteral, rejects private and loopback IPv4 ranges and tests an IPv6 value against the unspecified address, the loopback, the link-local prefix and the unique-local prefixes. A value such as [::ffff:127.0.0.1] matches none of them. The value is also recognised as an address literal rather than a name, so the path that re-checks addresses obtained from resolution is not taken. The HTTP client treats the mapped form as the embedded IPv4 address and connects to it, so an authenticated project member who can configure a webhook can direct the server at loopback services, private network ranges and link-local metadata endpoints, and the response is recorded where the webhook result can be read. Version 12.0.7 adds handling for the mapped range.
- CVE-2026-35053Critical
OneUptime is an open-source monitoring platform. Prior to version 10.0.42, the Worker service exposes workflow execution endpoints without authentication. An attacker who knows a workflow ID can execute arbitrary workflows with controlled input, enabling JavaScript code execution, notification abuse, and data manipulation.
- CVE-2026-34758Critical
OneUptime prior to version 10.0.42 allows unauthenticated access to Notification test and Phone Number management endpoints, enabling SMS/Call/Email/WhatsApp abuse and phone number purchase.
- CVE-2026-34759High
OneUptime before version 10.0.42 registers multiple notification API endpoints without authentication middleware, while sibling endpoints use it. Combined with a projectId leak from the public Status Page API, an unauthenticated attacker can purchase phone numbers on the victim's Twilio account and delete existing alerting numbers.
Original NVD description (English source)
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.