Security advisory

{
  "id": "bbe1d92c276e0b1c4478fd740c28a9fce48bdce1a529757d0bddf64d7c8287b1",
  "url": "https://osv.dev/vulnerability/CVE-2021-30479",
  "method": "structured",
  "payload": {
    "kind": "advisory",
    "title": "CVE-2021-30479",
    "summary": "An issue was discovered in Zulip Server before 3.4. A bug in the implementation of the all_public_streams API feature resulted in guest users being able to receive message traffic to public streams that should have been only accessible to members of the organization.",
    "evidence": "osv:CVE-2021-30479",
    "products": [],
    "severity": "medium",
    "structured": {
      "id": "CVE-2021-30479",
      "aliases": [
        "CVE-2021-30479"
      ],
      "metrics": [
        {
          "type": "CVSS_V3",
          "score": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:N/A:N"
        }
      ],
      "affected": [
        {
          "ranges": [
            {
              "repo": "https://github.com/zulip/zulip",
              "type": "GIT",
              "events": [
                {
                  "introduced": "0"
                },
                {
                  "fixed": "974b95b0956e6be5ef43683fbfac951d6460c802"
                }
              ],
              "database_specific": {
                "extracted_events": [
                  {
                    "cpe": "cpe:2.3:a:zulip:zulip_server:*:*:*:*:*:*:*:*",
                    "range": [
                      {
                        "introduced": "0"
                      },
                      {
                        "fixed": "3.4"
                      }
                    ],
                    "source": "CPE_RANGE"
                  }
                ]
              }
            }
          ],
          "versions": [
            "3.3",
            "3.2",
            "3.1",
            "4.0-dev",
            "3.0",
            "3.0-rc2",
            "3.0-rc1",
            "3.0-dev",
            "2.2-dev",
            "2.1.0",
            "2.1.0-rc1",
            "shared-0.0.2",
            "shared-0.0.1",
            "2.0.0",
            "2.1-dev",
            "2.0.0-rc1",
            "1.9.0",
            "1.9.0-rc3",
            "1.9.0-rc2",
            "1.8.0",
            "1.8.0-rc1",
            "1.7.0",
            "1.6.0",
            "1.5.0",
            "1.4.0",
            "1.3.13",
            "1.3.11",
            "1.3.10",
            "1.3.9",
            "1.3.8",
            "1.3.7",
            "1.3.6",
            "1.3.5",
            "1.3.4",
            "1.3.3",
            "1.3.2",
            "1.3.1",
            "1.3.0",
            "enterprise-1.2.0",
            "enterprise-1.1.5"
          ],
          "database_specific": {
            "source": "https://storage.googleapis.com/cve-osv-conversion/osv-output/CVE-2021-30479.json"
          }
        }
      ],
      "modified": "2026-10-24T10:30:42.514626518Z",
      "provider": "osv",
      "references": [
        "https://blog.zulip.com/2021/04/14/zulip-server-3-4/"
      ],
      "provider_metadata": {}
    },
    "related_cves": [
      {
        "value": "CVE-2021-30479",
        "evidence": "/id"
      }
    ],
    "security_relevant": true,
    "severity_evidence": "/severity/0/score"
  },
  "source_id": "core-osv",
  "document_id": 435403,
  "published_at": "2021-04-15T00:15:13.17+00:00"
}