SiYuan: A parser differential between the WebSocket keepalive exemption and the session quarantine allows unauthenticated access to the broadcast event stream

{
  "id": "1cb8dc27d2de5d7c3a2b8955294ff159afd18e7f9172081c0d461e5936363256",
  "url": "https://osv.dev/vulnerability/GHSA-c8w8-3pqp-wr83",
  "method": "structured",
  "payload": {
    "kind": "advisory",
    "title": "SiYuan: A parser differential between the WebSocket keepalive exemption and the session quarantine allows unauthenticated access to the broadcast event stream",
    "summary": "### Summary Two checks on the same WebSocket request URI parse it differently. The authentication exemption for keepalive sessions matches raw substrings, while the quarantine introduced to contain those sessions reads a parsed query parameter. Because Go's `url.Values.Get` returns only the first value for a repeated key, a single URI can satisfy the exemption and still resolve to a non-auth session identity. The result is that an unauthenticated remote caller connects to the kernel WebSocket with a valid access auth code configured, is placed in the general broadcast pool rather than the quarantined pool, and receives the live event stream. ### Details **The exemption matches substrings.** `kernel/server/serve.go:1222` on the development branch, `:1074` on master: ```go authOk = strings.Contains(s.Request.RequestURI, \"/ws?app=siyuan\") && strings.Contains(s.Request.RequestURI, \"&id=auth&type=auth\") ``` Neither operand is parsed. Any URI containing both literals is exempted, regardless of what the query actually resolves to. **The quarantine parses.** Commit `1e370e373` added the containment for exempted sessions at `kernel/util/websocket.go:171`: ```go id = session.Request.URL.Query().Get(\"id\") return \"auth\" == id ``` `url.Values.Get` returns the first value for a repeated key. **The differential.** For the URI: ``` /ws?app=siyuan&id=main&type=main&id=auth&type=auth ``` - It contains `/ws?app=siyuan` and `&id=auth&type=auth`, so `authOk` is true. No cookie, no JWT and no acce",
    "evidence": "osv:GHSA-c8w8-3pqp-wr83",
    "products": [
      {
        "name": {
          "value": "github.com/siyuan-note/siyuan/kernel",
          "evidence": "/affected/0/package/name"
        },
        "prerequisites": [],
        "fixed_versions": [
          {
            "value": "0.0.0-20260731131820-67bc300b6ea6",
            "evidence": "/affected/0/ranges"
          }
        ],
        "affected_versions": []
      }
    ],
    "severity": "high",
    "structured": {
      "id": "GHSA-c8w8-3pqp-wr83",
      "aliases": [
        "CVE-2026-73054",
        "GHSA-c8w8-3pqp-wr83"
      ],
      "metrics": [
        {
          "type": "CVSS_V3",
          "score": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:N"
        }
      ],
      "affected": [
        {
          "ranges": [
            {
              "type": "SEMVER",
              "events": [
                {
                  "introduced": "0"
                },
                {
                  "fixed": "0.0.0-20260731131820-67bc300b6ea6"
                }
              ]
            }
          ],
          "package": {
            "name": "github.com/siyuan-note/siyuan/kernel",
            "purl": "pkg:golang/github.com/siyuan-note/siyuan/kernel",
            "ecosystem": "Go"
          },
          "database_specific": {
            "source": "https://github.com/github/advisory-database/blob/main/advisories/github-reviewed/2026/10/GHSA-c8w8-3pqp-wr83/GHSA-c8w8-3pqp-wr83.json"
          }
        }
      ],
      "modified": "2026-10-23T18:45:09.519798674Z",
      "provider": "osv",
      "references": [
        "https://github.com/siyuan-note/siyuan/security/advisories/GHSA-c8w8-3pqp-wr83",
        "https://nvd.nist.gov/vuln/detail/CVE-2026-73054",
        "https://github.com/siyuan-note/siyuan/commit/67bc300b6ea6650d99dae55c827aeced419c8ac4",
        "https://github.com/siyuan-note/siyuan",
        "https://github.com/siyuan-note/siyuan/releases/tag/v3.7.4-alpha.4",
        "https://www.vulncheck.com/advisories/siyuan-before-authentication-bypass-via-websocket"
      ],
      "provider_metadata": {
        "cwe_ids": [
          "CWE-287"
        ],
        "severity": "HIGH",
        "github_reviewed": true,
        "nvd_published_at": null,
        "github_reviewed_at": "2026-10-23T18:34:09Z"
      }
    },
    "related_cves": [
      {
        "value": "CVE-2026-73054",
        "evidence": "/aliases"
      }
    ],
    "security_relevant": true,
    "severity_evidence": "/database_specific/severity"
  },
  "source_id": "core-osv",
  "document_id": 424607,
  "published_at": "2026-10-23T18:34:09+00:00"
}