GHSA-V5HF-F4C3-M5RV

Vulnerability from github – Published: 2026-03-11 00:34 – Updated: 2026-03-11 20:57
VLAI?
Summary
Parse Server vulnerable to stored XSS via file upload of HTML-renderable file types
Details

Impact

An attacker can upload a file with a file extension or content type that is not blocked by the default configuration of the Parse Server fileUpload.fileExtensions option. The file can contain malicious code, for example JavaScript in an SVG or XHTML file. When the file is accessed via its URL, the browser renders the file and executes the malicious code in the context of the Parse Server domain. This is a stored Cross-Site Scripting (XSS) vulnerability that can be exploited to steal session tokens, redirect users, or perform actions on behalf of other users.

Affected file extensions and content types include .svgz, .xht, .xml, .xsl, .xslt, and content types application/xhtml+xml and application/xslt+xml for extensionless uploads. Uploading of .html, .htm, .shtml, .xhtml, and .svg files was already blocked.

Patches

The fix adds the missing file extensions and content types to the default value of the fileUpload.fileExtensions server option.

Workarounds

Configure the fileUpload.fileExtensions server option to block the affected file extensions and content types.

References

  • GitHub security advisory: https://github.com/parse-community/parse-server/security/advisories/GHSA-v5hf-f4c3-m5rv
  • Fix Parse Server 9: https://github.com/parse-community/parse-server/releases/tag/9.6.0-alpha.4
  • Fix Parse Server 8: https://github.com/parse-community/parse-server/releases/tag/8.6.30
Severity ?
6.3 (Medium)
CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:A/VC:N/VI:N/VA:N/SC:H/SI:H/SA:N
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{
  "affected": [
    {
      "package": {
        "ecosystem": "npm",
        "name": "parse-server"
      },
      "ranges": [
        {
          "events": [
            {
              "introduced": "9.0.0-alpha.1"
            },
            {
              "fixed": "9.6.0-alpha.4"
            }
          ],
          "type": "ECOSYSTEM"
        }
      ]
    },
    {
      "package": {
        "ecosystem": "npm",
        "name": "parse-server"
      },
      "ranges": [
        {
          "events": [
            {
              "introduced": "0"
            },
            {
              "fixed": "8.6.30"
            }
          ],
          "type": "ECOSYSTEM"
        }
      ]
    }
  ],
  "aliases": [
    "CVE-2026-31868"
  ],
  "database_specific": {
    "cwe_ids": [
      "CWE-79"
    ],
    "github_reviewed": true,
    "github_reviewed_at": "2026-03-11T00:34:24Z",
    "nvd_published_at": "2026-03-11T18:16:25Z",
    "severity": "MODERATE"
  },
  "details": "### Impact\n\nAn attacker can upload a file with a file extension or content type that is not blocked by the default configuration of the Parse Server `fileUpload.fileExtensions` option. The file can contain malicious code, for example JavaScript in an SVG or XHTML file. When the file is accessed via its URL, the browser renders the file and executes the malicious code in the context of the Parse Server domain. This is a stored Cross-Site Scripting (XSS) vulnerability that can be exploited to steal session tokens, redirect users, or perform actions on behalf of other users.\n\nAffected file extensions and content types include `.svgz`, `.xht`, `.xml`, `.xsl`, `.xslt`, and content types `application/xhtml+xml` and `application/xslt+xml` for extensionless uploads. Uploading of `.html`, `.htm`, `.shtml`, `.xhtml`, and `.svg` files was already blocked.\n\n### Patches\n\nThe fix adds the missing file extensions and content types to the default value of the `fileUpload.fileExtensions` server option.\n\n### Workarounds\n\nConfigure the `fileUpload.fileExtensions` server option to block the affected file extensions and content types.\n\n### References\n\n- GitHub security advisory: https://github.com/parse-community/parse-server/security/advisories/GHSA-v5hf-f4c3-m5rv\n- Fix Parse Server 9: https://github.com/parse-community/parse-server/releases/tag/9.6.0-alpha.4\n- Fix Parse Server 8: https://github.com/parse-community/parse-server/releases/tag/8.6.30",
  "id": "GHSA-v5hf-f4c3-m5rv",
  "modified": "2026-03-11T20:57:39Z",
  "published": "2026-03-11T00:34:24Z",
  "references": [
    {
      "type": "WEB",
      "url": "https://github.com/parse-community/parse-server/security/advisories/GHSA-v5hf-f4c3-m5rv"
    },
    {
      "type": "ADVISORY",
      "url": "https://nvd.nist.gov/vuln/detail/CVE-2026-31868"
    },
    {
      "type": "PACKAGE",
      "url": "https://github.com/parse-community/parse-server"
    },
    {
      "type": "WEB",
      "url": "https://github.com/parse-community/parse-server/releases/tag/8.6.30"
    },
    {
      "type": "WEB",
      "url": "https://github.com/parse-community/parse-server/releases/tag/9.6.0-alpha.4"
    }
  ],
  "schema_version": "1.4.0",
  "severity": [
    {
      "score": "CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:A/VC:N/VI:N/VA:N/SC:H/SI:H/SA:N",
      "type": "CVSS_V4"
    }
  ],
  "summary": "Parse Server vulnerable to stored XSS via file upload of HTML-renderable file types"
}


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  • Seen: The vulnerability was mentioned, discussed, or observed by the user.
  • Confirmed: The vulnerability has been validated from an analyst's perspective.
  • Published Proof of Concept: A public proof of concept is available for this vulnerability.
  • Exploited: The vulnerability was observed as exploited by the user who reported the sighting.
  • Patched: The vulnerability was observed as successfully patched by the user who reported the sighting.
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  • Not confirmed: The user expressed doubt about the validity of the vulnerability.
  • Not patched: The vulnerability was not observed as successfully patched by the user who reported the sighting.



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