CVE-2026-49819

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 v3 9.8 CRITICAL

9.8^/10

CVSS v3 : CRITICAL

Vector :

Exploitability : 3.9 / Impact : 5.9

Attack Vector NETWORK

Attack Complexity LOW

Privileges Required NONE

User Interaction NONE

Confidentiality Impact HIGH

Integrity Impact HIGH

Availability Impact HIGH

Scope UNCHANGED

References

Link	Resource
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

Configurations

No configuration.

History

No history.

Information

Published : 2026-08-13 00:17

Updated : 2026-09-09 21:02

NVD link : CVE-2026-49819

Mitre link : CVE-2026-49819

CVE.ORG link : CVE-2026-49819

JSON object : View

Products Affected

No product.

CWE

CWE-78

Improper Neutralization of Special Elements used in an OS Command ('OS Command Injection')

CWE-269

Improper Privilege Management

CWE-306

Missing Authentication for Critical Function

CWE-862

Missing Authorization

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