ghsa-cpm7-cfpx-3hvp

{
  "affected": [
    {
      "database_specific": {
        "last_known_affected_version_range": "<= 8.38.0",
        "source": "https://github.com/github/advisory-database/blob/main/advisories/github-reviewed/2026/04/GHSA-cpm7-cfpx-3hvp/GHSA-cpm7-cfpx-3hvp.json"
      },
      "package": {
        "ecosystem": "Maven",
        "name": "gov.nsa.emissary:emissary",
        "purl": "pkg:maven/gov.nsa.emissary/emissary"
      },
      "ranges": [
        {
          "events": [
            {
              "introduced": "0"
            },
            {
              "fixed": "8.39.0"
            }
          ],
          "type": "ECOSYSTEM"
        }
      ],
      "versions": [
        "8.0.0",
        "8.1.0",
        "8.10.0",
        "8.11.0",
        "8.11.1",
        "8.12.0",
        "8.13.0",
        "8.14.0",
        "8.15.0",
        "8.16.0",
        "8.17.0",
        "8.18.0",
        "8.19.0",
        "8.19.1",
        "8.2.0",
        "8.20.0",
        "8.21.0",
        "8.22.0",
        "8.23.0",
        "8.24.0",
        "8.25.0",
        "8.26.0",
        "8.27.0",
        "8.28.0",
        "8.29.0",
        "8.3.0",
        "8.30.0",
        "8.31.0",
        "8.32.0",
        "8.33.0",
        "8.34.0",
        "8.35.0",
        "8.36.0",
        "8.37.0",
        "8.38.0",
        "8.4.0",
        "8.5.0",
        "8.6.0",
        "8.7.0",
        "8.7.1",
        "8.8.0",
        "8.9.0"
      ]
    }
  ],
  "aliases": [
    "CVE-2026-35571"
  ],
  "database_specific": {
    "cwe_ids": [
      "CWE-79"
    ],
    "github_reviewed": true,
    "github_reviewed_at": "2026-04-07T20:17:14Z",
    "nvd_published_at": "2026-04-07T16:16:29Z",
    "severity": "MODERATE"
  },
  "details": "## Summary\n\nMustache navigation templates interpolated configuration-controlled link values\ndirectly into `href` attributes without URL scheme validation. An administrator\nwho could modify the `navItems` configuration could inject `javascript:` URIs,\nenabling stored cross-site scripting (XSS) against other authenticated users\nviewing the Emissary web interface.\n\n## Details\n\n### Vulnerable code — `nav.mustache` (line 10)\n\n```html\n{{#navItems}}\n<li class=\"nav-item\">\n  <a class=\"nav-link\" href=\"{{link}}\">{{display}}</a>\n</li>\n{{/navItems}}\n```\n\nThe `{{link}}` value was rendered without any scheme validation. Mustache's\ndefault HTML escaping protects against injection of new HTML tags but does\n**not** prevent `javascript:` URIs in `href` attributes, since `javascript:`\ncontains no characters that HTML-escaping would alter.\n\n### Attack vector\n\nAn administrator sets a navigation item's link to:\n```\njavascript:alert(document.cookie)\n```\n\nAny authenticated user who clicks the navigation link executes the script in\ntheir browser context.\n\n### Impact\n\n- Session hijacking via cookie theft\n- Actions performed on behalf of the victim user\n- Requires administrative access to modify navigation configuration\n- Requires user interaction (clicking the malicious link)\n\n### Mitigating factors\n\n- Exploitation requires administrative access to modify the `navItems`\n  configuration\n- User interaction (clicking the link) is required\n- The Emissary web interface is typically accessed only by authenticated\n  operators within a trusted network\n\n## Remediation\n\nFixed in [PR #1293](https://github.com/NationalSecurityAgency/emissary/pull/1293),\nmerged into release 8.39.0.\n\n### Server-side link validation — `NavAction.java`\n\nAn allowlist regex was added that only permits `http://`, `https://`, or\nsite-relative (`/`) URLs:\n\n```java\nprivate static final Pattern VALID_LINK = Pattern.compile(\"^(https?:/)?/.*\");\n\nprivate static boolean isValidLink(String link) {\n    if (!VALID_LINK.matcher(link).matches()) {\n        logger.warn(\"Skipping invalid navigation link '{}'\", link);\n        return false;\n    }\n    return true;\n}\n```\n\nInvalid links are logged and silently dropped from the rendered navigation.\n\n### Template hardening — `nav.mustache`\n\nAdded `rel=\"noopener noreferrer\"` to all navigation link anchor tags as a\ndefense-in-depth measure:\n\n```html\n<a class=\"nav-link\" href=\"{{link}}\" rel=\"noopener noreferrer\">{{display}}</a>\n```\n\nTests were added to verify that `javascript:` and `ftp://` URIs are rejected\nwhile `http://`, `https://`, and site-relative (`/path`) links are accepted.\n\n## Workarounds\n\nIf upgrading is not immediately possible, audit the navigation configuration\nto ensure all `navItems` link values use only `http://`, `https://`, or\nrelative (`/`) URL schemes.\n\n## References\n\n- [PR #1293 — validate nav links](https://github.com/NationalSecurityAgency/emissary/pull/1293)\n- Original report: GHSA-wjqm-p579-x3ww",
  "id": "GHSA-cpm7-cfpx-3hvp",
  "modified": "2026-11-04T22:15:03.697846410Z",
  "published": "2026-04-07T20:17:14Z",
  "references": [
    {
      "type": "WEB",
      "url": "https://github.com/NationalSecurityAgency/emissary/security/advisories/GHSA-cpm7-cfpx-3hvp"
    },
    {
      "type": "ADVISORY",
      "url": "https://nvd.nist.gov/vuln/detail/CVE-2026-35571"
    },
    {
      "type": "WEB",
      "url": "https://github.com/NationalSecurityAgency/emissary/pull/1293"
    },
    {
      "type": "WEB",
      "url": "https://github.com/NationalSecurityAgency/emissary/commit/e2078417464b9004620dde28dcbca2f73ea06c13"
    },
    {
      "type": "PACKAGE",
      "url": "https://github.com/NationalSecurityAgency/emissary"
    },
    {
      "type": "WEB",
      "url": "https://github.com/NationalSecurityAgency/emissary/releases/tag/8.39.0"
    }
  ],
  "schema_version": "1.9.2",
  "severity": [
    {
      "score": "CVSS:3.1/AV:N/AC:L/PR:H/UI:R/S:C/C:L/I:L/A:N",
      "type": "CVSS_V3"
    }
  ],
  "summary": "Emissary has Stored XSS via Navigation Template Link Injection"
}