{"id":"CVE-2021-43843","details":"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 `\u003cblockquote\u003e` 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 `\u003cblockquote\u003e` with multibyte characters.","aliases":["GHSA-hp68-xhvj-x6j6"],"modified":"2026-07-09T01:06:16.472046Z","published":"2021-12-20T22:15:07.817Z","related":["GHSA-55xv-f85c-248q","GHSA-hp68-xhvj-x6j6"],"references":[{"type":"ADVISORY","url":"https://github.com/yhatt/jsx-slack/releases/tag/v4.5.2"},{"type":"FIX","url":"https://github.com/yhatt/jsx-slack/commit/46bc88391d89d5fda4ce689e18ca080bcdd29ecc"},{"type":"FIX","url":"https://github.com/yhatt/jsx-slack/security/advisories/GHSA-55xv-f85c-248q"},{"type":"FIX","url":"https://github.com/yhatt/jsx-slack/security/advisories/GHSA-hp68-xhvj-x6j6"}],"affected":[{"ranges":[{"type":"GIT","repo":"https://github.com/yhatt/jsx-slack","events":[{"introduced":"0"},{"fixed":"2fc5567b48bf8cbb8e9902c09e2b5a56f4068e19"},{"fixed":"46bc88391d89d5fda4ce689e18ca080bcdd29ecc"}],"database_specific":{"cpe":"cpe:2.3:a:jsx-slack_project:jsx-slack:*:*:*:*:*:node.js:*:*","extracted_events":[{"introduced":"0"},{"fixed":"4.5.2"}],"source":["CPE_RANGE","REFERENCES"]}}],"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"}}],"schema_version":"1.7.5","severity":[{"type":"CVSS_V3","score":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H"}]}