CVE-2026-28787: high-severity vulnerability in oneuptime
OneUptime has WebAuthn 2FA bypass: server accepts client-supplied challenge instead of server-stored value, allowing credential replay
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21Vexday Risk Score
No sign of exploitation. No public exploitation artifact known so far.
ssvc Trackcvss 8.2epss 0.3%
OneUptime is a solution for monitoring and managing online services. In version 10.0.11 and prior, the WebAuthn authentication implementation does not store the challenge on the server side. Instead, the challenge is returned to the client and accepted back from the client request body during verification. This violates the WebAuthn specification (W3C Web Authentication Level 2, §13.4.3) and allows an attacker who has obtained a valid WebAuthn assertion (e.g., via XSS, MitM, or log exposure) to replay it indefinitely, completely bypassing the second-factor authentication. No known patches are available.
CVSS:3.1/AV:N/AC:H/PR:L/UI:N/S:C/C:H/I:H/A:N
Affected products
OneUptime · oneuptimeRelated CVEs — oneuptime
In the same product, most dangerous first.
CVE-2026-27728CRITICALOneUptime: OS Command Injection in Probe NetworkPathMonitor via unsanitized destination in traceroute exec()EPSS 2.0%CVE-2026-30957CRITICALOneUptime Synthetic Monitor RCE via exposed Playwright browser objectEPSS 1.3%CVE-2026-30958HIGHOneUptime: Path Traversal — Arbitrary File Read (No Auth)EPSS 1.2%CVE-2026-33396CRITICALOneUptime has sandbox escape in Synthetic Monitor Playwright runtime allows project members to execute arbitrary commands on ProbeEPSS 0.8%CVE-2026-32306CRITICALOneUptime ClickHouse SQL Injection via Aggregate Query ParametersEPSS 0.7%CVE-2024-29194HIGHOneUptime Vulnerable to a Privilege Escalation via Local Storage Key ManipulationEPSS 0.7%