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Medium

Presenton < 0.8.8-beta - Authentication Bypass of Session Auth via Unprotected MCP Endpoint

Type: advisorySources: OSV

Presenton before 0.8.8-beta bundles an MCP server that, on server/Docker deployments configured with session authentication (AUTH_USERNAME/AUTH_PASSWORD), is reachable unauthenticated at /mcp because the nginx front-end does not apply the auth_request gate to that path and the MCP server auto-mints a valid internal session token for the configured user. A remote unauthenticated attacker can invoke MCP tools such as generate_presentation, performing authenticated application actions, consuming the operators configured LLM API keys, and creating presentations in the operators instance. The Electron desktop build is not affected (MCP disabled).

Products
Not specified
Affected versions
Not specified
Fixed versions
Not specified
CVEs
CVE-2026-58446
Confirmed fixed CVEs
Not specified
Updated in this feed
3 Nov 2026, 09:54 UTC · Revision 1

Source evidence

Presenton < 0.8.8-beta - Authentication Bypass of Session Auth via Unprotected MCP Endpoint

core-osv · Original source

Published 30 Jun 2026, 21:05 UTC

Presenton before 0.8.8-beta bundles an MCP server that, on server/Docker deployments configured with session authentication (AUTH_USERNAME/AUTH_PASSWORD), is reachable unauthenticated at /mcp because the nginx front-end does not apply the auth_request gate to that path and the MCP server auto-mints a valid internal session token for the configured user. A remote unauthenticated attacker can invoke MCP tools such as generate_presentation, performing authenticated application actions, consuming the operators configured LLM API keys, and creating presentations in the operators instance. The Electron desktop build is not affected (MCP disabled).

osv:CVE-2026-58446
Complete source record
{
  "id": "3fe55674162e18a1487f493df15383a756ab3bab4cae7d1de18187ebc9d7e163",
  "url": "https://osv.dev/vulnerability/CVE-2026-58446",
  "method": "structured",
  "payload": {
    "kind": "advisory",
    "title": "Presenton < 0.8.8-beta - Authentication Bypass of Session Auth via Unprotected MCP Endpoint",
    "summary": "Presenton before 0.8.8-beta bundles an MCP server that, on server/Docker deployments configured with session authentication (AUTH_USERNAME/AUTH_PASSWORD), is reachable unauthenticated at /mcp because the nginx front-end does not apply the auth_request gate to that path and the MCP server auto-mints a valid internal session token for the configured user. A remote unauthenticated attacker can invoke MCP tools such as generate_presentation, performing authenticated application actions, consuming the operators configured LLM API keys, and creating presentations in the operators instance. The Electron desktop build is not affected (MCP disabled).",
    "evidence": "osv:CVE-2026-58446",
    "products": [],
    "severity": "medium",
    "structured": {
      "id": "CVE-2026-58446",
      "aliases": [
        "CVE-2026-58446"
      ],
      "metrics": [
        {
          "type": "CVSS_V4",
          "score": "CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:L/VA:L/SC:N/SI:N/SA:N"
        }
      ],
      "affected": [
        {
          "ranges": [
            {
              "repo": "https://github.com/presenton/presenton",
              "type": "GIT",
              "events": [
                {
                  "introduced": "0"
                },
                {
                  "fixed": "c1cdd7b8d0c922621e65094aaaebde4fbeb89095"
                },
                {
                  "fixed": "a1103dcef3c761cc8bab44e2862c81a49969abd7"
                }
              ],
              "database_specific": {
                "extracted_events": [
                  {
                    "range": [
                      {
                        "introduced": "0"
                      },
                      {
                        "fixed": "0.8.8-beta"
                      }
                    ],
                    "source": "AFFECTED_FIELD",
                    "strategy": "StandardRange"
                  },
                  {
                    "range": [
                      {
                        "fixed": "c1cdd7b8d0c922621e65094aaaebde4fbeb89095"
                      }
                    ],
                    "source": "REFERENCES_TAG",
                    "original_tag": "electron-v0.8.8-beta"
                  },
                  {
                    "range": [
                      {
                        "fixed": "a1103dcef3c761cc8bab44e2862c81a49969abd7"
                      }
                    ],
                    "source": "REFERENCES_COMMIT"
                  }
                ]
              }
            }
          ],
          "versions": [
            "electron-v0.8.6-beta",
            "v0.8.6-beta",
            "v0.8.4-beta",
            "v0.8.5-beta",
            "v0.8.3-beta",
            "v0.8.2-beta",
            "v0.8.1-beta",
            "v0.8.0-beta",
            "v0.7.3-beta",
            "electron-v0.7.3-beta",
            "electron-v0.7.2-beta",
            "electron-v0.7.1-beta",
            "electron-v0.7.0-beta",
            "electron-v0.6.3-beta",
            "electron-v0.6.2-beta",
            "electron-v0.6.0-beta",
            "v0.5.18-beta",
            "v0.5.17-beta",
            "v0.5.16-beta",
            "v0.5.15-beta",
            "v0.5.14-beta",
            "v0.5.12-beta",
            "v0.5.11-beta",
            "0.5.10",
            "v0.5.9-beta",
            "v0.5.8-beta",
            "v0.5.7-beta",
            "v0.5.6-beta",
            "v0.5.5",
            "v0.5.4-beta",
            "v0.5.3-beta",
            "v0.5.2-beta",
            "v0.5.1-beta",
            "v0.5.0-beta",
            "v0.4.8-beta",
            "v0.4.7-beta",
            "v0.4.5-beta",
            "v0.4.4-beta",
            "v0.4.3-beta",
            "v0.4.1-beta",
            "v0.4.0-beta",
            "v0.3.7-beta",
            "v0.3.6-beta",
            "v0.3.5-beta",
            "v0.3.4-beta",
            "v0.3.2-beta",
            "v0.3.0-beta",
            "v0.2.1-beta",
            "v0.2.0-beta",
            "v0.1.0-beta"
          ],
          "database_specific": {
            "source": "https://storage.googleapis.com/cve-osv-conversion/osv-output/CVE-2026-58446.json"
          }
        }
      ],
      "modified": "2026-10-28T02:30:27.764116816Z",
      "provider": "osv",
      "references": [
        "https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/58xxx/CVE-2026-58446.json",
        "https://github.com/presenton/presenton/releases/tag/electron-v0.8.8-beta",
        "https://nvd.nist.gov/vuln/detail/CVE-2026-58446",
        "https://www.vulncheck.com/advisories/presenton-beta-authentication-bypass-of-session-auth-via-unprotected-mcp-endpoint",
        "https://github.com/presenton/presenton/pull/679",
        "https://github.com/presenton/presenton/commit/a1103dcef3c761cc8bab44e2862c81a49969abd7",
        "https://github.com/presenton/presenton",
        "https://github.com/presenton/presenton/issues/678"
      ],
      "provider_metadata": {
        "cwe_ids": [
          "CWE-306"
        ],
        "cna_assigner": "VulnCheck",
        "osv_generated_from": "https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/58xxx/CVE-2026-58446.json"
      }
    },
    "related_cves": [
      {
        "value": "CVE-2026-58446",
        "evidence": "/id"
      }
    ],
    "security_relevant": true,
    "severity_evidence": "/severity/0/score"
  },
  "source_id": "core-osv",
  "document_id": 494332,
  "published_at": "2026-06-30T21:05:15.949+00:00"
}