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CVE-2026-28787

Hackerbay Oneuptime authentication bypass

8.2 HIGHPublic exploitEPSS 0.40%
  1. Published6 Mar 2026

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 3.1 breakdown

Attack vectorNetwork
Attack complexityHigh
Privileges requiredLow
User interactionNone
ScopeChanged
ConfidentialityHigh
IntegrityHigh
AvailabilityNone
CVSS:3.1/AV:N/AC:H/PR:L/UI:N/S:C/C:H/I:H/A:N

Affected products

Hackerbay Oneuptime≤ 10.0.11

Remediation

No fixed version is recorded in the NVD data. Check the vendor advisory for the latest guidance.

References

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Frequently asked

Is CVE-2026-28787 being actively exploited?

CVE-2026-28787 is not in the CISA KEV catalog. A public exploit reference exists, so treat it as exploitable. Its EPSS exploit probability is 0.40%.

How severe is CVE-2026-28787?

CVE-2026-28787 has a CVSS 3.1 base score of 8.2, rated high. EPSS estimates a 0.40% probability of exploitation.

Which products are affected by CVE-2026-28787?

Affected products include Hackerbay Oneuptime.

How do I fix CVE-2026-28787?

Apply the vendor's patch or advisory guidance, then verify no affected versions remain across your devices.

How Secuno handles this

Secuno correlates vulnerabilities like CVE-2026-28787 against the real software inventory on every managed device, as each hourly inventory arrives. Rather than a static severity, each match is scored in context: exploit availability, EPSS, the asset's exposure, and business criticality decide where it lands in the queue. If an affected version is present anywhere across your portfolio, it surfaces automatically with a prioritised remediation path.

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Data from the NVD, CISA KEV catalog and FIRST EPSS. CVSS 3.1 base score shown where available.