{"id":"CVE-2020-26256","aliases":["GHSA-8cv5-p934-3hwp"],"url":"https://o3.security/vulnerability/CVE-2020-26256","summary":"Denial of service in fast-csv","details":"### Impact\nPossible ReDoS (Regular Expression Denial of Service) when using `ignoreEmpty` option when parsing.\n\n### Patches\nThis has been patched in `v4.3.6`\n\n### Workarounds\nYou will only be affected by this if you use the `ignoreEmpty` parsing option. If you do use this option it is recommended that you upgrade to the latest version `v4.3.6`\n\n### References\n\nThis vulnerability was found using a [CodeQL](https://securitylab.github.com/tools/codeql) query which identified `EMPTY_ROW_REGEXP` regular expression as vulnerable.\n[Link to query run](https://lgtm.com/query/8609731774537641779/). \n\n### For more information\nIf you have any questions or comments about this advisory:\n* Open an issue in [fast-csv](https://github.com/C2FO/fast-csv)","published":"2020-12-08T22:15:17.540Z","modified":"2026-07-09T00:37:57.506477Z","cvss":{"score":6.5,"severity":"MEDIUM","vector":"CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H"},"epss":null,"cisaKev":null,"exploitsKnown":null,"affectedPackages":[{"ecosystem":"npm","name":"fast-csv","fixedVersion":"4.3.6"},{"ecosystem":"npm","name":"@fast-csv/parse","fixedVersion":"4.3.6"}],"fix":{"url":"https://github.com/C2FO/fast-csv/commit/4bbd39f26a8cd7382151ab4f5fb102234b2f829e","label":"C2FO/fast-csv@4bbd39f"},"references":[{"type":"WEB","url":"https://www.npmjs.com/package/%40fast-csv/parse"},{"type":"ADVISORY","url":"https://github.com/C2FO/fast-csv/issues/540"},{"type":"ADVISORY","url":"https://github.com/C2FO/fast-csv/security/advisories/GHSA-8cv5-p934-3hwp"},{"type":"ADVISORY","url":"https://www.npmjs.com/package/fast-csv"},{"type":"FIX","url":"https://github.com/C2FO/fast-csv/commit/4bbd39f26a8cd7382151ab4f5fb102234b2f829e"},{"type":"EVIDENCE","url":"https://lgtm.com/query/8609731774537641779/"},{"type":"ADVISORY","url":"https://nvd.nist.gov/vuln/detail/CVE-2020-26256"},{"type":"PACKAGE","url":"https://github.com/C2FO/fast-csv"},{"type":"WEB","url":"https://lgtm.com/query/8609731774537641779"},{"type":"WEB","url":"https://www.npmjs.com/advisories/1587"},{"type":"WEB","url":"https://www.npmjs.com/advisories/1588"},{"type":"WEB","url":"https://www.npmjs.com/package/@fast-csv/parse"}],"provenance":{"sources":["OSV.dev","FIRST.org (EPSS)"],"lastVerified":"2026-07-09T00:37:57.506477Z"}}