CVE-2026-49819

CRITICALPre-NVD 9.89.8—
EchelonGraph scoreMEDIUM confidence

This critical-severity CVE scores 9.8 under a secondary CVSS source (NVD's own analysis pending). EPSS exploit probability: 0.8%, top 45% of all CVEs by exploit prediction. GitHub Security Advisory data not yet ingested — confidence will rise once GHSA publishes (typical lag: hours to days for open-source ecosystem CVEs; never for infrastructure-only CVEs).

Triggered by: NVD CVSS baseline
Sources: epss, secondary
Elevated
9.8EG
EchelonGraph verdictPlan a fixSerious severity, but no confirmed exploitation yet.
  • High severity, but no confirmed exploitation yet
CISA-KEV: Not listedEPSS PROB: 1%CVSS: 9.8Exploit: Elevated riskExposed: 0

No vendor fix yet — apply a workaround or compensating control (WAF / firewall / segmentation) and watch for a patch.

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
EG Score
9.8(medium)
EG Risk
75(Attend)
EG Risk 75/100SSVC: Attend

EG Risk is EchelonGraph's 0–100 priority score: it fuses intrinsic severity with real-world exploitation and automatability so you can rank equal-severity CVEs and fix the most dangerous first. Higher = act sooner. Distinct from the 0–10 EG Score (severity).

How it’s computed
Severity98% × 45%
Exploitation40% × 40%
Automatability100% × 15%
Action: Remediate soon — notable exploitation risk.
EPSS PROB
1%
EPSS %ILE
55%
KEV
Not listed

Published

August 12, 2026

Last Modified

September 9, 2026

Advisory Details (2)

Auto-updated Sep 16, 2026
🔬 Proof of concept available. Patch available. Sources: github_release, github.
github Patch Available🟡 PoC Available

UpSnap <= 5.3.5 - Unauthenticated Initial-Superuser Takeover Chains to Root RCE via wake_cmd · Advisory · seriousm4x/UpSnap · GitHub

https://github.com/seriousm4x/UpSnap/security/advisories/GHSA-w4jr-728f-5jhq
github_release Patch Available

5.4.0

Patch available: seriousm4x/UpSnap 5.4.0

https://github.com/seriousm4x/UpSnap/releases/tag/5.4.0

Weakness Classification(4)

MITRE Common Weakness Enumeration — the root-cause categories this CVE belongs to.

Data Freshness Timeline

(refreshed 11× in last 7d / 51× in last 30d)

Each row is a source pipeline that fetched or updated this CVE on that date, with what changed. For example, "NVD update" means NVD published or revised its analysis for this CVE; "MITRE cvelistV5" means we ingested or refreshed it from the CNA feed. Most recent first.

  1. 2026-09-21 00:14 UTCEG score recompute
  2. 2026-09-20 20:16 UTCEPSS rescore
  3. 2026-09-19 16:20 UTCEG score recompute
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  25. 2026-09-06 13:47 UTCEPSS rescore
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  1. 2026-09-05 19:01 UTCEG score recompute
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  3. 2026-09-04 07:52 UTCEG score recompute
  4. 2026-09-04 05:06 UTCEPSS rescore
  5. 2026-09-02 23:24 UTCEG score recompute
  6. 2026-09-02 14:12 UTCEPSS rescore
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  8. 2026-09-01 13:54 UTCEPSS rescore
  9. 2026-09-01 06:21 UTCEG score recompute
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  11. 2026-08-30 22:07 UTCEG score recompute
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  15. 2026-08-29 08:25 UTCEG score recompute
  16. 2026-08-28 21:41 UTCEPSS rescore
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  18. 2026-08-27 14:25 UTCEPSS rescore
  19. 2026-08-26 18:47 UTCEG score recompute
  20. 2026-08-26 14:46 UTCEPSS rescore
  21. 2026-08-25 15:15 UTCEG score recompute
  22. 2026-08-25 13:49 UTCEPSS rescore
  23. 2026-08-24 17:16 UTCEG score recompute
  24. 2026-08-24 12:29 UTCEG score recompute
  25. 2026-08-23 03:32 UTCEG score recompute
  26. 2026-08-23 00:19 UTCEPSS rescore
  27. 2026-08-22 02:00 UTCEG score recompute
  28. 2026-08-21 23:49 UTCEPSS rescore
  29. 2026-08-21 00:07 UTCEG score recompute
  30. 2026-08-20 22:55 UTCEPSS rescore
  31. 2026-08-19 18:32 UTCEG score recompute
  32. 2026-08-19 17:04 UTCEPSS rescore
  33. 2026-08-18 15:13 UTCEG score recompute
  34. 2026-08-18 13:48 UTCEPSS rescore
  35. 2026-08-17 16:29 UTCEG score recompute
  36. 2026-08-17 13:47 UTCEPSS rescore
  37. 2026-08-16 18:16 UTCEG score recompute
  38. 2026-08-16 14:56 UTCEPSS rescore
  39. 2026-08-16 03:39 UTCEG score recompute
  40. 2026-08-16 02:14 UTCEPSS rescore
  41. 2026-08-15 02:05 UTCEG score recompute
  42. 2026-08-15 01:30 UTCEPSS rescore
  43. 2026-08-14 00:33 UTCEG score recompute
  44. 2026-08-13 22:00 UTCEPSS rescore
  45. 2026-08-13 17:14 UTCEG score recompute
  46. 2026-08-13 13:35 UTCEG score recompute
  47. 2026-08-13 13:18 UTCEG score recompute
  48. 2026-08-13 00:22 UTCEG score recompute
  49. 2026-08-12 23:26 UTCEG score recompute
  50. 2026-08-12 23:25 UTCMITRE cvelistV5first tracked

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Frequently asked(5)

What is CVE-2026-49819?
CVE-2026-49819 is a critical vulnerability published on August 12, 2026. 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…
When was CVE-2026-49819 disclosed?
CVE-2026-49819 was first published in the National Vulnerability Database on August 12, 2026, with the most recent update on September 9, 2026. EchelonGraph re-ingests CVE updates from NVD on a 2-hour cycle, so this page reflects the latest published state.
Is CVE-2026-49819 actively exploited?
CVE-2026-49819 is not currently on CISA's Known Exploited Vulnerabilities catalog. FIRST EPSS estimates a 1% probability of exploitation in the next 30 days, which ranks it in the top 45.2% of all scored CVEs.
What is the CVSS score of CVE-2026-49819?
CVE-2026-49819 has a CVSS v3 base score of 9.8 (NVD).
How do I remediate CVE-2026-49819?
Patch to the fixed version published by the affected vendor. Where vendor advisories exist for CVE-2026-49819, EchelonGraph cross-links them in the Vendor Advisories panel below — those typically contain the canonical remediation steps, fixed version numbers, and any vendor-specific mitigations.

Dependency Blast Radius

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