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

{
  "id": "a18df233f6d3f473e58b81a357f644dd9eccb0f1d4b2d27c20b6ebb3488282e6",
  "url": "https://osv.dev/vulnerability/CVE-2026-49819",
  "method": "structured",
  "payload": {
    "kind": "advisory",
    "title": "UpSnap - Unauthenticated Initial-Superuser Takeover Chains to Root RCE via wake_cmd",
    "summary": "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.",
    "evidence": "osv:CVE-2026-49819",
    "products": [],
    "severity": "critical",
    "structured": {
      "id": "CVE-2026-49819",
      "aliases": [
        "CVE-2026-49819",
        "GHSA-w4jr-728f-5jhq"
      ],
      "metrics": [
        {
          "type": "CVSS_V3",
          "score": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H"
        }
      ],
      "affected": [
        {
          "ranges": [
            {
              "repo": "https://github.com/seriousm4x/upsnap",
              "type": "GIT",
              "events": [
                {
                  "introduced": "47b81553befa785b73ddc8aff2c6774975791ff2"
                },
                {
                  "fixed": "92f9e295d5f761d874a6701245b2e38dc42cb85a"
                }
              ],
              "database_specific": {
                "extracted_events": [
                  {
                    "range": [
                      {
                        "introduced": "4.4.1"
                      },
                      {
                        "fixed": "5.4.0"
                      }
                    ],
                    "source": "AFFECTED_FIELD",
                    "strategy": "StringRangeExpression"
                  },
                  {
                    "range": [
                      {
                        "fixed": "92f9e295d5f761d874a6701245b2e38dc42cb85a"
                      }
                    ],
                    "source": "REFERENCES_TAG",
                    "original_tag": "5.4.0"
                  }
                ]
              }
            }
          ],
          "versions": [
            "5.3.5",
            "5.3.4",
            "5.3.3",
            "5.3.2",
            "5.3.2-beta.0",
            "5.3.1",
            "5.3.0",
            "5.3.0-beta.0",
            "5.2.8",
            "5.2.7",
            "5.2.6",
            "5.2.5",
            "5.2.4",
            "5.2.3",
            "5.2.2",
            "5.2.1",
            "5.2.0",
            "5.2.0-beta.1",
            "5.2.0-beta.0",
            "5.1.10-beta.1",
            "5.1.9",
            "5.1.8",
            "5.1.7",
            "5.1.6",
            "5.1.5",
            "5.1.4",
            "5.1.3",
            "5.1.2",
            "5.1.1",
            "5.1.0",
            "5.0.8",
            "5.0.7",
            "5.0.6",
            "5.0.5",
            "5.0.5-beta.1",
            "5.0.4",
            "5.0.3",
            "5.0.2",
            "5.0.1",
            "5.0.1-beta.2",
            "5.0.1-beta.1",
            "5.0.0",
            "5.0.0-beta.3",
            "5.0.0-beta.2",
            "5.0.0-beta.1",
            "4.6.0",
            "4.5.1",
            "4.5.0",
            "4.4.2",
            "4.4.2-beta.2",
            "4.4.2-beta.1",
            "4.4.1"
          ],
          "database_specific": {
            "source": "https://storage.googleapis.com/cve-osv-conversion/osv-output/CVE-2026-49819.json"
          }
        }
      ],
      "modified": "2026-10-28T02:30:27.087090242Z",
      "provider": "osv",
      "references": [
        "https://github.com/seriousm4x/UpSnap/releases/tag/5.4.0",
        "https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/49xxx/CVE-2026-49819.json",
        "https://github.com/seriousm4x/UpSnap/security/advisories/GHSA-w4jr-728f-5jhq",
        "https://nvd.nist.gov/vuln/detail/CVE-2026-49819"
      ],
      "provider_metadata": {
        "cwe_ids": [
          "CWE-269",
          "CWE-306",
          "CWE-78",
          "CWE-862"
        ],
        "cna_assigner": "GitHub_M",
        "osv_generated_from": "https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/49xxx/CVE-2026-49819.json"
      }
    },
    "related_cves": [
      {
        "value": "CVE-2026-49819",
        "evidence": "/id"
      }
    ],
    "security_relevant": true,
    "severity_evidence": "/severity/0/score"
  },
  "source_id": "core-osv",
  "document_id": 493917,
  "published_at": "2026-08-12T23:13:46.298+00:00"
}