Vulnerability Description
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 Score
HIGH
Affected Products
| Vendor | Product | Versions |
|---|---|---|
| Hackerbay | Oneuptime | <= 10.0.11 |
Related Weaknesses (CWE)
References
- https://github.com/OneUptime/oneuptime/security/advisories/GHSA-gjjc-pcwp-c74mExploitVendor Advisory
FAQ
What is CVE-2026-28787?
CVE-2026-28787 is a vulnerability with a CVSS score of 8.2 (HIGH). 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, ...
How severe is CVE-2026-28787?
CVE-2026-28787 has been rated HIGH with a CVSS base score of 8.2/10. Review the CVSS metrics above for detailed severity breakdown.
Is there a patch for CVE-2026-28787?
Check the references section above for vendor advisories and patch information. Affected products include: Hackerbay Oneuptime.