Security advisory

{
  "id": "5b210e2c20cf08a25fb00e1000c61fb75444304265dbf5474948daa2be7f3210",
  "url": "https://osv.dev/vulnerability/CVE-2021-43843",
  "method": "structured",
  "payload": {
    "kind": "advisory",
    "title": "CVE-2021-43843",
    "summary": "jsx-slack is a package for building JSON objects for Slack block kit surfaces from JSX. The maintainers found the patch for CVE-2021-43838 in jsx-slack v4.5.1 is insufficient tfor protection from a Regular Expression Denial of Service (ReDoS) attack. If an attacker can put a lot of JSX elements into `` tag _with including multibyte characters_, an internal regular expression for escaping characters may consume an excessive amount of computing resources. v4.5.1 passes the test against ASCII characters but misses the case of multibyte characters. jsx-slack v4.5.2 has updated regular expressions for escaping blockquote characters to prevent catastrophic backtracking. It is also including an updated test case to confirm rendering multiple tags in `` with multibyte characters.",
    "evidence": "osv:CVE-2021-43843",
    "products": [],
    "severity": "high",
    "structured": {
      "id": "CVE-2021-43843",
      "aliases": [
        "CVE-2021-43843",
        "GHSA-hp68-xhvj-x6j6"
      ],
      "metrics": [
        {
          "type": "CVSS_V3",
          "score": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H"
        }
      ],
      "affected": [
        {
          "ranges": [
            {
              "repo": "https://github.com/yhatt/jsx-slack",
              "type": "GIT",
              "events": [
                {
                  "introduced": "0"
                },
                {
                  "fixed": "2fc5567b48bf8cbb8e9902c09e2b5a56f4068e19"
                },
                {
                  "fixed": "46bc88391d89d5fda4ce689e18ca080bcdd29ecc"
                }
              ],
              "database_specific": {
                "extracted_events": [
                  {
                    "cpe": "cpe:2.3:a:jsx-slack_project:jsx-slack:*:*:*:*:*:node.js:*:*",
                    "range": [
                      {
                        "introduced": "0"
                      },
                      {
                        "fixed": "4.5.2"
                      }
                    ],
                    "source": "CPE_RANGE"
                  },
                  {
                    "range": [
                      {
                        "fixed": "46bc88391d89d5fda4ce689e18ca080bcdd29ecc"
                      }
                    ],
                    "source": "REFERENCES_COMMIT"
                  },
                  {
                    "range": [
                      {
                        "fixed": "2fc5567b48bf8cbb8e9902c09e2b5a56f4068e19"
                      }
                    ],
                    "source": "REFERENCES_TAG",
                    "original_tag": "v4.5.2"
                  }
                ]
              }
            }
          ],
          "versions": [
            "v4.5.1",
            "v4.5.0",
            "v4.4.3",
            "v4.4.2",
            "v4.4.1",
            "v4.4.0",
            "v4.3.0",
            "v4.2.1",
            "v4.2.0",
            "v4.1.0",
            "v4.0.0",
            "v3.0.0",
            "v2.6.0",
            "v2.5.1",
            "v2.5.0",
            "v2.4.0",
            "v2.3.0",
            "v2.2.1",
            "v2.2.0",
            "v2.1.0",
            "v2.0.0",
            "v1.7.0",
            "v1.6.0",
            "v1.5.1",
            "v1.5.0",
            "v1.4.0",
            "v1.3.1",
            "v1.3.0",
            "v1.2.0",
            "v1.1.0",
            "v1.0.0",
            "v0.12.0",
            "v0.11.1",
            "v0.11.0",
            "v0.10.2",
            "v0.10.1",
            "v0.10.0",
            "v0.9.2",
            "v0.9.1",
            "v0.9.0",
            "v0.8.1",
            "v0.8.0",
            "v0.7.0",
            "v0.6.0",
            "v0.5.1",
            "v0.5.0",
            "v0.4.3",
            "v0.4.2",
            "v0.4.1",
            "v0.4.0",
            "v0.3.0",
            "v0.2.0",
            "v0.1.0"
          ],
          "database_specific": {
            "source": "https://storage.googleapis.com/cve-osv-conversion/osv-output/CVE-2021-43843.json"
          }
        }
      ],
      "modified": "2026-10-20T10:55:04.957100344Z",
      "provider": "osv",
      "references": [
        "https://github.com/yhatt/jsx-slack/releases/tag/v4.5.2",
        "https://github.com/yhatt/jsx-slack/commit/46bc88391d89d5fda4ce689e18ca080bcdd29ecc",
        "https://github.com/yhatt/jsx-slack/security/advisories/GHSA-55xv-f85c-248q",
        "https://github.com/yhatt/jsx-slack/security/advisories/GHSA-hp68-xhvj-x6j6"
      ],
      "provider_metadata": {}
    },
    "related_cves": [
      {
        "value": "CVE-2021-43843",
        "evidence": "/id"
      }
    ],
    "security_relevant": true,
    "severity_evidence": "/severity/0/score"
  },
  "source_id": "core-osv",
  "document_id": 386844,
  "published_at": "2021-12-20T22:15:07.817+00:00"
}