{
  "schemaVersion": 1,
  "attribution": [
    {
      "source": "CISA Known Exploited Vulnerabilities",
      "url": "https://www.cisa.gov/known-exploited-vulnerabilities-catalog",
      "licence": "US government work"
    },
    {
      "source": "GitHub Advisory Database",
      "url": "https://github.com/advisories",
      "licence": "CC BY 4.0"
    },
    {
      "source": "Have I Been Pwned",
      "url": "https://haveibeenpwned.com/",
      "licence": "CC BY 4.0"
    },
    {
      "source": "CVE Program (CVE records)",
      "url": "https://www.cve.org/Legal/TermsOfUse",
      "licence": "CVE Terms of Use",
      "notice": "Copyright © 1999-2026, The MITRE Corporation. CVE is a trademark and the CVE logo is a registered trademark of The MITRE Corporation.",
      "terms": "CVE Usage: MITRE hereby grants you a perpetual, worldwide, non-exclusive, no-charge, royalty-free, irrevocable copyright license to reproduce, prepare derivative works of, publicly display, publicly perform, sublicense, and distribute Common Vulnerabilities and Exposures (CVE™). Any copy you make for such purposes is authorized provided that you reproduce MITRE's copyright designation and this license in any such copy."
    },
    {
      "source": "FIRST EPSS",
      "url": "https://www.first.org/epss/",
      "licence": "free to use; FIRST requests attribution"
    }
  ],
  "record": {
    "id": "CVE-2021-21290",
    "sourceURL": "https://www.cve.org/CVERecord?id=CVE-2021-21290",
    "idYear": 2021,
    "status": "PUBLISHED",
    "publishedAt": "2021-02-08T20:10:16.000Z",
    "updatedAt": "2026-10-08T21:14:01.568Z",
    "importedAt": "2026-10-24T01:56:26.894Z",
    "snapshot": {
      "id": "cve_2026-10-24_midnight_baseline",
      "at": "2026-10-24T00:00:00.000Z",
      "source": "https://github.com/CVEProject/cvelistV5/releases/tag/cve_2026-10-24_0100Z"
    },
    "facts": {
      "title": "Local Information Disclosure Vulnerability in Netty on Unix-Like systems due temporary files",
      "summary": "Netty is an open-source, asynchronous event-driven network application framework for rapid development of maintainable high performance protocol servers & clients. In Netty before version 4.1.59.Final there is a vulnerability on Unix-like systems involving an insecure temp file. When netty's multipart decoders are used local information disclosure can occur via the local system temporary directory if temporary storing uploads on the disk is enabled. On unix-like systems, the temporary directory is shared between all user. As such, writing to this directory using APIs that do not explicitly set the file/directory permissions can lead to information disclosure. Of note, this does not impact modern MacOS Operating Systems. The method \"File.createTempFile\" on unix-like systems creates a random file, but, by default will create this file with the permissions \"-rw-r--r--\". Thus, if sensitive information is written to this file, other local users can read this information. This is the case in netty's \"AbstractDiskHttpData\" is vulnerable. This has been fixed in version 4.1.59.Final. As a workaround, one may specify your own \"java.io.tmpdir\" when you start the JVM or use \"DefaultHttpDataFactory.setBaseDir(...)\" to set the directory to something that is only readable by the current user.",
      "affected": [
        {
          "vendor": "netty",
          "product": "netty",
          "versions": [
            {
              "version": "< 4.1.59.Final",
              "status": "affected"
            }
          ]
        }
      ]
    }
  }
}