CVE-2026-49819: CWE-78: Improper Neutralization of Special Elements used in an OS Command ('OS Command Injection') in seriousm4x UpSnap
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.
AI Analysis
Technical Summary
UpSnap, a wake on LAN web application, suffers from an authentication bypass and privilege escalation vulnerability in versions 4.4.1 through 5.3.5. The vulnerable endpoint POST /api/upsnap/init-superuser in pb.HandlerInitSuperuser lacks authentication, setup tokens, IP allow-listing, and rate limiting, relying solely on a totalSuperusers > 0 check that is false on fresh installs. This allows an unauthenticated attacker to register the initial superuser account, obtain a long-lived JWT, and escalate privileges to root remote code execution via exec.CommandContext executing shell commands. The vulnerability is fixed in version 5.4.0.
Potential Impact
An unauthenticated network-adjacent attacker can create the initial superuser account, gaining full administrative access. This leads to complete system compromise including remote code execution with root privileges. The vulnerability has a CVSS score of 9.8 (critical), indicating high impact on confidentiality, integrity, and availability.
Mitigation Recommendations
Upgrade to UpSnap version 5.4.0 or later, which fixes the authentication bypass and privilege escalation vulnerability. Until patched, restrict network access to the vulnerable endpoint and monitor for unauthorized superuser registrations. Patch status is not explicitly confirmed in vendor advisories; however, version 5.4.0 is stated as the fix.
CVE-2026-49819: CWE-78: Improper Neutralization of Special Elements used in an OS Command ('OS Command Injection') in seriousm4x UpSnap
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 v3.1
Score 9.8critical
Affected software
seriousm4x
UpSnap
pkg:github/seriousm4x/UpSnapRun on your own infrastructure? Check whether these packages are installed with threat-finder — our free open-source scanner.
AI-Powered Analysis
Machine-generated threat intelligence
Technical Analysis
UpSnap, a wake on LAN web application, suffers from an authentication bypass and privilege escalation vulnerability in versions 4.4.1 through 5.3.5. The vulnerable endpoint POST /api/upsnap/init-superuser in pb.HandlerInitSuperuser lacks authentication, setup tokens, IP allow-listing, and rate limiting, relying solely on a totalSuperusers > 0 check that is false on fresh installs. This allows an unauthenticated attacker to register the initial superuser account, obtain a long-lived JWT, and escalate privileges to root remote code execution via exec.CommandContext executing shell commands. The vulnerability is fixed in version 5.4.0.
Potential Impact
An unauthenticated network-adjacent attacker can create the initial superuser account, gaining full administrative access. This leads to complete system compromise including remote code execution with root privileges. The vulnerability has a CVSS score of 9.8 (critical), indicating high impact on confidentiality, integrity, and availability.
Mitigation Recommendations
Upgrade to UpSnap version 5.4.0 or later, which fixes the authentication bypass and privilege escalation vulnerability. Until patched, restrict network access to the vulnerable endpoint and monitor for unauthorized superuser registrations. Patch status is not explicitly confirmed in vendor advisories; however, version 5.4.0 is stated as the fix.
Technical Details
- Data Version
- 5.2
- Assigner Short Name
- GitHub_M
- Date Reserved
- 2026-06-01T18:50:36.055Z
- Cvss Version
- 3.1
- State
- PUBLISHED
Threat ID: 6a7d0145bf8831d539509f78
Added to database: 08/12/2026, 23:27:01 UTC
Last enriched: 08/12/2026, 23:41:06 UTC
Last updated: 09/27/2026, 01:47:42 UTC
Views: 112
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