{"id":"CVE-2023-34104","aliases":["EUVD-2023-1717","GHSA-6w63-h3fj-q4vw"],"status":"published","title":"Regex Injection via Doctype Entities","description":"fast-xml-parser is an open source, pure javascript xml parser. fast-xml-parser allows special characters in entity names, which are not escaped or sanitized. Since the entity name is used for creating a regex for searching and replacing entities in the XML body, an attacker can abuse it for denial of service (DoS) attacks. By crafting an entity name that results in an intentionally bad performing regex and utilizing it in the entity replacement step of the parser, this can cause the parser to stall for an indefinite amount of time. This problem has been resolved in v4.2.4. Users are advised to upgrade. Users unable to upgrade should avoid using DOCTYPE parsing by setting the `processEntities: false` option.","severity":{"version":"3.1","score":7.5,"vector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H","level":"high","assessor":"cna","from":"cve"},"epss":{"day":"2026-11-11","score":0.01126,"percentile":0.66713,"model":"v2026.06.15"},"facts":{"in_kev":false,"known_exploited":false,"public_exploit":false,"fix_available":true},"cwes":["CWE-1333","CWE-400"],"published":"2023-06-06T17:33:13Z","modified":"2026-11-11T02:47:31Z","fixes":[{"ecosystem":"npm","package":"fast-xml-parser","fixed_in":["4.2.4"],"sources":["ghsa","osv"]}],"affected":[{"source":"ghsa","ecosystem":"npm","package":"fast-xml-parser","ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"4.1.3"},{"fixed":"4.2.4"}]}]},{"source":"osv","ecosystem":"npm","package":"fast-xml-parser","ranges":[{"type":"SEMVER","events":[{"introduced":"4.1.3"},{"fixed":"4.2.4"}]}]}],"products":[{"vendor":"naturalintelligence","product":"fast-xml-parser"}],"references":[{"url":"https://github.com/NaturalIntelligence/fast-xml-parser/security/advisories/GHSA-6w63-h3fj-q4vw","tags":["x_refsource_CONFIRM","x_transferred","Mitigation","Vendor Advisory","advisory","web"]},{"url":"https://github.com/NaturalIntelligence/fast-xml-parser/commit/39b0e050bb909e8499478657f84a3076e39ce76c","tags":["x_refsource_MISC","x_transferred","Patch","fix","web"]},{"url":"https://github.com/NaturalIntelligence/fast-xml-parser/commit/a4bdced80369892ee413bf08e28b78795a2b0d5b","tags":["x_refsource_MISC","x_transferred","fix","web"]},{"url":"https://nvd.nist.gov/vuln/detail/CVE-2023-34104","tags":["advisory"]},{"url":"https://github.com/advisories/GHSA-6w63-h3fj-q4vw"},{"url":"https://github.com/CVEProject/cvelistV5/tree/main/cves/2023/34xxx/CVE-2023-34104.json","tags":["advisory"]},{"url":"https://github.com/NaturalIntelligence/fast-xml-parser","tags":["package"]}],"sources":{"cve":[{"id":"CVE-2023-34104","title":"Regex Injection via Doctype Entities","description":"fast-xml-parser is an open source, pure javascript xml parser. fast-xml-parser allows special characters in entity names, which are not escaped or sanitized. Since the entity name is used for creating a regex for searching and replacing entities in the XML body, an attacker can abuse it for denial of service (DoS) attacks. By crafting an entity name that results in an intentionally bad performing regex and utilizing it in the entity replacement step of the parser, this can cause the parser to stall for an indefinite amount of time. This problem has been resolved in v4.2.4. Users are advised to upgrade. Users unable to upgrade should avoid using DOCTYPE parsing by setting the `processEntities: false` option.","status":"published","published":"2023-06-06T17:35:54.699Z","modified":"2024-08-02T16:01:54.11Z","cvss":[{"version":"3.1","score":7.5,"vector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H","level":"high","assessor":"cna"}],"cwes":["CWE-400","CWE-1333"],"updated_at":"2026-11-02T14:35:35.912488Z"}],"euvd":[{"id":"EUVD-2023-1717","description":"fast-xml-parser is an open source, pure javascript xml parser. fast-xml-parser allows special characters in entity names, which are not escaped or sanitized. Since the entity name is used for creating a regex for searching and replacing entities in the XML body, an attacker can abuse it for denial of service (DoS) attacks. By crafting an entity name that results in an intentionally bad performing regex and utilizing it in the entity replacement step of the parser, this can cause the parser to stall for an indefinite amount of time. This problem has been resolved in v4.2.4. Users are advised to upgrade. Users unable to upgrade should avoid using DOCTYPE parsing by setting the `processEntities: false` option.","status":"published","published":"2023-06-06T17:35:54Z","modified":"2024-08-02T16:01:54Z","cvss":[{"version":"3.1","score":7.5,"vector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H","level":"high"}],"updated_at":"2026-11-03T03:50:04.380287Z"}],"ghsa":[{"id":"GHSA-6w63-h3fj-q4vw","title":"fast-xml-parser vulnerable to Regex Injection via Doctype Entities","description":"### Impact\n\"fast-xml-parser\" allows special characters in entity names, which are not escaped or sanitized. Since the entity name is used for creating a regex for searching and replacing entities in the XML body, an attacker can abuse it for DoS attacks. By crafting an entity name that results in an intentionally bad performing regex and utilizing it in the entity replacement step of the parser, this can cause the parser to stall for an indefinite amount of time.\n\n### Patches\nThe problem has been resolved in v4.2.4\n\n### Workarounds\nAvoid using DOCTYPE parsing by `processEntities: false` option.","status":"published","published":"2023-06-06T17:33:13Z","modified":"2026-03-09T15:58:39Z","cvss":[{"version":"3.1","score":7.5,"vector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H","level":"high"}],"cwes":["CWE-400","CWE-1333"],"updated_at":"2026-11-02T14:39:33.538417Z"}],"nvd":[{"id":"CVE-2023-34104","description":"fast-xml-parser is an open source, pure javascript xml parser. fast-xml-parser allows special characters in entity names, which are not escaped or sanitized. Since the entity name is used for creating a regex for searching and replacing entities in the XML body, an attacker can abuse it for denial of service (DoS) attacks. By crafting an entity name that results in an intentionally bad performing regex and utilizing it in the entity replacement step of the parser, this can cause the parser to stall for an indefinite amount of time. This problem has been resolved in v4.2.4. Users are advised to upgrade. Users unable to upgrade should avoid using DOCTYPE parsing by setting the `processEntities: false` option.","status":"published","published":"2023-06-06T18:15:11.643Z","modified":"2026-06-17T06:02:54.207Z","cvss":[{"version":"3.1","score":7.5,"vector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H","level":"high","assessor":"secondary"},{"version":"3.1","score":7.5,"vector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H","level":"high","assessor":"primary"}],"cwes":["CWE-400","CWE-1333"],"updated_at":"2026-11-02T14:08:05.329837Z"}],"osv":[{"id":"CVE-2023-34104","title":"Regex Injection via Doctype Entities","description":"fast-xml-parser is an open source, pure javascript xml parser. fast-xml-parser allows special characters in entity names, which are not escaped or sanitized. Since the entity name is used for creating a regex for searching and replacing entities in the XML body, an attacker can abuse it for denial of service (DoS) attacks. By crafting an entity name that results in an intentionally bad performing regex and utilizing it in the entity replacement step of the parser, this can cause the parser to stall for an indefinite amount of time. This problem has been resolved in v4.2.4. Users are advised to upgrade. Users unable to upgrade should avoid using DOCTYPE parsing by setting the `processEntities: false` option.","status":"published","published":"2023-06-06T17:35:54.699Z","modified":"2026-11-11T10:46:25.769595703Z","cvss":[{"version":"3.1","score":7.5,"vector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H","level":"high"}],"cwes":["CWE-1333","CWE-400"],"updated_at":"2026-11-11T03:22:28.447808Z"},{"id":"GHSA-6w63-h3fj-q4vw","title":"fast-xml-parser vulnerable to Regex Injection via Doctype Entities","description":"### Impact\n\"fast-xml-parser\" allows special characters in entity names, which are not escaped or sanitized. Since the entity name is used for creating a regex for searching and replacing entities in the XML body, an attacker can abuse it for DoS attacks. By crafting an entity name that results in an intentionally bad performing regex and utilizing it in the entity replacement step of the parser, this can cause the parser to stall for an indefinite amount of time.\n\n### Patches\nThe problem has been resolved in v4.2.4\n\n### Workarounds\nAvoid using DOCTYPE parsing by `processEntities: false` option.","status":"published","published":"2023-06-06T17:33:13Z","modified":"2026-03-09T16:01:35.601971Z","cvss":[{"version":"3.1","score":7.5,"vector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H","level":"high"}],"cwes":["CWE-1333","CWE-400"],"updated_at":"2026-11-02T15:46:40.308826Z"}]}}