Security advisory

{
  "id": "536610e3667ac06aa976656ffceb25d3b0a05b3bd0929ea2e5384162c57f8d8a",
  "url": "https://osv.dev/vulnerability/CVE-2019-16216",
  "method": "structured",
  "payload": {
    "kind": "advisory",
    "title": "CVE-2019-16216",
    "summary": "Zulip server before 2.0.5 incompletely validated the MIME types of uploaded files. A user who is logged into the server could upload files of certain types to mount a stored cross-site scripting attack on other logged-in users. On a Zulip server using the default local uploads backend, the attack is only effective against browsers lacking support for Content-Security-Policy such as Internet Explorer 11. On a Zulip server using the S3 uploads backend, the attack is confined to the origin of the configured S3 uploads hostname and cannot reach the Zulip server itself.",
    "evidence": "osv:CVE-2019-16216",
    "products": [],
    "severity": "medium",
    "structured": {
      "id": "CVE-2019-16216",
      "aliases": [
        "CVE-2019-16216"
      ],
      "metrics": [
        {
          "type": "CVSS_V3",
          "score": "CVSS:3.1/AV:N/AC:L/PR:L/UI:R/S:C/C:L/I:L/A:N"
        }
      ],
      "affected": [
        {
          "ranges": [
            {
              "repo": "https://github.com/zulip/zulip",
              "type": "GIT",
              "events": [
                {
                  "introduced": "a6a5636a326d41c82a21f5fe2b26463162b37621"
                },
                {
                  "fixed": "2bb3af1ade5bb3613dc88d44164abbe1230cd679"
                },
                {
                  "fixed": "1195841dfb9aa26b3b0dabc6f05d72e4af25be3e"
                }
              ],
              "database_specific": {
                "extracted_events": [
                  {
                    "cpe": "cpe:2.3:a:zulip:zulip_server:*:*:*:*:*:*:*:*",
                    "range": [
                      {
                        "introduced": "1.8.0"
                      },
                      {
                        "fixed": "2.0.5"
                      }
                    ],
                    "source": "CPE_RANGE"
                  },
                  {
                    "range": [
                      {
                        "fixed": "1195841dfb9aa26b3b0dabc6f05d72e4af25be3e"
                      }
                    ],
                    "source": "REFERENCES_COMMIT"
                  }
                ]
              }
            }
          ],
          "versions": [
            "2.0.4",
            "2.0.3",
            "2.0.2",
            "2.0.1",
            "2.0.0",
            "2.0.0-rc1",
            "1.9.0",
            "1.9.0-rc3",
            "1.9.0-rc2",
            "1.8.0"
          ],
          "database_specific": {
            "source": "https://storage.googleapis.com/cve-osv-conversion/osv-output/CVE-2019-16216.json"
          }
        }
      ],
      "modified": "2026-10-20T10:52:25.955960798Z",
      "provider": "osv",
      "references": [
        "https://blog.zulip.org/2019/09/11/zulip-server-2-0-5-security-release/",
        "https://github.com/zulip/zulip/commit/1195841dfb9aa26b3b0dabc6f05d72e4af25be3e"
      ],
      "provider_metadata": {}
    },
    "related_cves": [
      {
        "value": "CVE-2019-16216",
        "evidence": "/id"
      }
    ],
    "security_relevant": true,
    "severity_evidence": "/severity/0/score"
  },
  "source_id": "core-osv",
  "document_id": 383642,
  "published_at": "2019-09-18T12:15:10.99+00:00"
}