Vulnerability Description
UpSnap is a wake on lan web app. Versions 4.4.1 through 5.3.5 are vulnerable to a missing-authentication / privilege-escalation chain in `pb.HandlerInitSuperuser` (`backend/pb/handlers.go:249`), reachable as `POST /api/upsnap/init-superuser`. The vulnerable code lacks any authentication, setup token, IP allow-list, or rate limit and is gated only by a `totalSuperusers > 0` count check — a condition that is false on every fresh install — allowing an unauthenticated network-adjacent attacker to register the initial superuser account, receive a long-lived JWT, and pivot to root remote code execution at `backend/networking/wake.go:43` (`exec.CommandContext(ctx, "/bin/sh", "-c", wake_cmd)`). Version 5.4.0 fixes the issue.
CVSS Score
CRITICAL
Related Weaknesses (CWE)
References
- https://github.com/seriousm4x/UpSnap/releases/tag/5.4.0
- https://github.com/seriousm4x/UpSnap/security/advisories/GHSA-w4jr-728f-5jhq
- https://github.com/seriousm4x/UpSnap/security/advisories/GHSA-w4jr-728f-5jhq
FAQ
What is CVE-2026-49819?
CVE-2026-49819 is a vulnerability with a CVSS score of 9.8 (CRITICAL). UpSnap is a wake on lan web app. Versions 4.4.1 through 5.3.5 are vulnerable to a missing-authentication / privilege-escalation chain in `pb.HandlerInitSuperuser` (`backend/pb/handlers.go:249`), reach...
How severe is CVE-2026-49819?
CVE-2026-49819 has been rated CRITICAL with a CVSS base score of 9.8/10. This is considered a critical vulnerability requiring immediate attention.
Is there a patch for CVE-2026-49819?
Check the references section above for vendor advisories and patch information. Review vendor security bulletins for remediation guidance.