What’s Vulnerable › Vulnerabilities

CVE-2026-119552: Uptime Kuma through 2.5.8 Race Condition Admin Creation via Setup Handler

• Severity: medium (CVSS 4.8 v3.1)
• Exploited in the wild: not listed in CISA KEV
• EPSS: 0.2% probability of exploitation in the next 30 days
• Public exploit or detection template: none known
• Published: 2026-10-30 · updated 2026-10-30
• Weakness: CWE-367

Description

Uptime Kuma through 2.5.8 contains a race condition in the Socket.IO first-run setup handler that allows unauthenticated attackers to create an additional administrator account. Attackers can send concurrent setup requests during the bcrypt hashing window to bypass the empty user table check, then modify monitors, API keys, and enable disableAuth.

Affected products

• louislam uptime-kuma: through 2.5.8

References

• https://abraxaslabs.tech/research/uptime-kuma-setup-toctou
• https://github.com/louislam/uptime-kuma
• https://github.com/louislam/uptime-kuma/blob/2.5.8/server/server.js#L705-L722
• https://www.vulncheck.com/advisories/uptime-kuma-through-2.5.8-race-condition-admin-creation-via-setup-handler

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