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High 8.2Published Mar 5, 2026

CVE-2026-28787OneUptime has WebAuthn 2FA bypass: server accepts client-supplied challenge instead of server-stored value, allowing credential replay

Updated under an hour ago ()

Does this affect you?

It affects oneuptime and 1 other product. Add what you run to find out whether that includes you.

No exploitation reported and no EPSS estimate yet.

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
8.2 HIGH (v3.1, CNA)CVSS:3.1/AV:N/AC:H/PR:L/UI:N/S:C/C:H/I:H/A:N
Weakness (CWE)
CWE-287, CWE-294
Known exploited
Not in CISA's KEV catalog
EPSS (exploitation in the next 30 days)
Not loaded for this CVE
Assigned by
GitHub_M
NVD analysis
Analyzed
Record last updated
Mar 9, 2026
First seen by InfoSec Signals
Oct 9, 2026

Affected products

Affected products
OneUptime oneuptime
oneuptime:oneuptime (from the name)
through 10.0.11
CNA record
hackerbay oneuptime
hackerbay:oneuptime
through 10.0.11
NVD

References

References

The CVE record is authoritative. Products marked “from the name” were identified from the CNA's free-text names, not a CPE, and are matched less certainly. This product uses the NVD API but is not endorsed or certified by the NVD.

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