Security advisory

{
  "id": "e1b5238965f16186ac2e746c2473c3b25590158ca17f2e4368eef212f2ba5cbe",
  "url": "https://osv.dev/vulnerability/CVE-2021-41115",
  "method": "structured",
  "payload": {
    "kind": "advisory",
    "title": "CVE-2021-41115",
    "summary": "Zulip is an open source team chat server. In affected versions Zulip allows organization administrators on a server to configure \"linkifiers\" that automatically create links from messages that users send, detected via arbitrary regular expressions. Malicious organization administrators could subject the server to a denial-of-service via regular expression complexity attacks; most simply, by configuring a quadratic-time regular expression in a linkifier, and sending messages that exploited it. A regular expression attempted to parse the user-provided regexes to verify that they were safe from ReDoS -- this was both insufficient, as well as _itself_ subject to ReDoS if the organization administrator entered a sufficiently complex invalid regex. Affected users should [upgrade to the just-released Zulip 4.7](https://zulip.readthedocs.io/en/latest/production/upgrade-or-modify.html#upgrading-to-a-release), or [`main`](https://zulip.readthedocs.io/en/latest/production/upgrade-or-modify.html#upgrading-from-a-git-repository).",
    "evidence": "osv:CVE-2021-41115",
    "products": [],
    "severity": "medium",
    "structured": {
      "id": "CVE-2021-41115",
      "aliases": [
        "CVE-2021-41115",
        "GHSA-4h36-mqfq-42jg"
      ],
      "metrics": [
        {
          "type": "CVSS_V3",
          "score": "CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H"
        }
      ],
      "affected": [
        {
          "ranges": [
            {
              "repo": "https://github.com/zulip/zulip",
              "type": "GIT",
              "events": [
                {
                  "introduced": "0"
                },
                {
                  "fixed": "4e724c1ec659086740d02eeab2789c4b07c6d822"
                },
                {
                  "fixed": "e2d303c1bb5f538d17dc3d9134bc8858bdece781"
                }
              ],
              "database_specific": {
                "extracted_events": [
                  {
                    "cpe": "cpe:2.3:a:zulip:zulip:*:*:*:*:*:*:*:*",
                    "range": [
                      {
                        "introduced": "0"
                      },
                      {
                        "fixed": "4.7"
                      }
                    ],
                    "source": "CPE_RANGE"
                  },
                  {
                    "range": [
                      {
                        "fixed": "e2d303c1bb5f538d17dc3d9134bc8858bdece781"
                      }
                    ],
                    "source": "REFERENCES_COMMIT"
                  }
                ]
              }
            }
          ],
          "versions": [
            "4.6",
            "4.5",
            "4.4",
            "4.3",
            "4.2",
            "4.1",
            "4.0",
            "shared-0.0.5",
            "shared-0.0.4",
            "shared-0.0.3",
            "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-2021-41115.json"
          }
        }
      ],
      "modified": "2026-10-24T10:50:25.643451888Z",
      "provider": "osv",
      "references": [
        "https://github.com/zulip/zulip/commit/e2d303c1bb5f538d17dc3d9134bc8858bdece781",
        "https://github.com/zulip/zulip/security/advisories/GHSA-4h36-mqfq-42jg",
        "https://securitylab.github.com/advisories/GHSL-2021-118-zulip-zulip/"
      ],
      "provider_metadata": {
        "unresolved_ranges": [
          {
            "cpes": [
              "cpe:2.3:a:zulip:zulip:*:*:*:*:*:*:*:*"
            ],
            "vendor_product": "zulip:zulip",
            "extracted_events": [
              {
                "range": [
                  {
                    "fixed": "4.7"
                  }
                ],
                "source": "CPE_RANGE"
              }
            ]
          }
        ]
      }
    },
    "related_cves": [
      {
        "value": "CVE-2021-41115",
        "evidence": "/id"
      }
    ],
    "security_relevant": true,
    "severity_evidence": "/severity/0/score"
  },
  "source_id": "core-osv",
  "document_id": 442155,
  "published_at": "2021-10-07T23:15:08.027+00:00"
}