Vulnerability · Published Aug 12, 2026 · Assigned by GitHub_M

CVE-2026-49819UpSnap - Unauthenticated Initial-Superuser Takeover Chains to Root RCE via wake_cmd

Critical 9.8

In plain English

A critical-severity OS command injection in UpSnap from seriousm4x. Proof-of-concept exploit code is public. The chance it is exploited in the next 30 days is estimated at 1.1% (higher than 65% of all known vulnerabilities).

Severity (CVSS 3.1)9.8Critical

Exploit odds (30 days)1.1%top 34.7% of all CVEs

Exploited in the wildNo reportsCISA SSVC: poc

Attack toolingNoneno public tooling known

Official 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.

Affected products (as reported)

Vendor	Product	Versions
seriousm4x	UpSnap	>= 4.4.1, < 5.4.0

Weakness: CWE-78, CWE-269, CWE-306, CWE-862 · Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H

References

https://github.com/seriousm4x/UpSnap/security/advisories/GHSA-w4jr-728f-5jhq x_refsource_CONFIRM
https://github.com/seriousm4x/UpSnap/releases/tag/5.4.0 x_refsource_MISC