{"id":"GHSA-hwhf-64mh-r662","summary":"ReDoS vulnerability in parser_apache2","details":"### Impact\nparser_apache2 plugin in Fluentd v0.14.14 to v1.14.1 suffers from a regular expression denial of service (ReDoS) vulnerability. A broken apache log with a certain pattern of string can spend too much time in a regular expression, resulting in the potential for a DoS attack.\n\n### Patches\nv1.14.2\n\n### Workarounds\nEither of the following:\n\n* Don't use parser_apache2 for parsing logs which cannot guarantee generated by Apache.\n* Put patched version of parser_apache2.rb into /etc/fluent/plugin  directory (or any other directories specified by the environment variable `FLUENT_PLUGIN` or `--plugin` option of fluentd).\n\n### References\n* [CVE-2021-41186](http://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2021-41186)\n* [GHSA-hwhf-64mh-r662](https://github.com/fluent/fluentd/security/advisories/GHSA-hwhf-64mh-r662)\n* [GHSL-2021-102](https://securitylab.github.com/advisories/GHSL-2021-102-fluent-fluentd/)\n* https://github.com/fluent/fluentd/blob/master/CHANGELOG.md#v1142\n","aliases":["BIT-fluentd-2021-41186","CVE-2021-41186"],"modified":"2026-07-08T06:28:53.596219161Z","published":"2021-11-01T19:16:31Z","database_specific":{"github_reviewed":true,"github_reviewed_at":"2021-10-29T13:44:13Z","nvd_published_at":"2021-10-29T14:15:00Z","cwe_ids":["CWE-400"],"severity":"MODERATE"},"references":[{"type":"WEB","url":"https://github.com/fluent/fluentd/security/advisories/GHSA-hwhf-64mh-r662"},{"type":"ADVISORY","url":"https://nvd.nist.gov/vuln/detail/CVE-2021-41186"},{"type":"WEB","url":"https://github.com/fluent/fluentd/commit/5482a3d049dab351de0be68f4b4bc562319d8511"},{"type":"PACKAGE","url":"https://github.com/fluent/fluentd"},{"type":"WEB","url":"https://github.com/fluent/fluentd/blob/master/CHANGELOG.md#v1142"},{"type":"WEB","url":"https://github.com/github/securitylab-vulnerabilities/blob/52dc4a2a828c6dc24231967c2937ad92038184a9/vendor_reports/GHSL-2021-102-fluent-fluentd.md"},{"type":"WEB","url":"https://github.com/rubysec/ruby-advisory-db/blob/master/gems/fluentd/CVE-2021-41186.yml"}],"affected":[{"package":{"name":"fluentd","ecosystem":"RubyGems","purl":"pkg:gem/fluentd"},"ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0.14.14"},{"fixed":"1.14.2"}]}],"versions":["0.14.14","0.14.15","0.14.16","0.14.17","0.14.18","0.14.19","0.14.20","0.14.20.rc1","0.14.21","0.14.22","0.14.22.rc1","0.14.22.rc2","0.14.23","0.14.23.rc1","0.14.24","0.14.25","1.0.0","1.0.0.rc1","1.0.1","1.0.2","1.1.0","1.1.1","1.1.2","1.1.3","1.10.0","1.10.1","1.10.2","1.10.3","1.10.4","1.11.0","1.11.1","1.11.2","1.11.3","1.11.4","1.11.5","1.12.0","1.12.0.rc1","1.12.0.rc2","1.12.1","1.12.2","1.12.3","1.12.4","1.13.0","1.13.1","1.13.2","1.13.3","1.14.0","1.14.0.rc","1.14.1","1.2.0","1.2.0.pre1","1.2.1","1.2.2","1.2.3","1.2.4","1.2.4.rc1","1.2.5","1.2.5.rc1","1.2.6","1.3.0","1.3.1","1.3.2","1.3.3","1.4.0","1.4.1","1.4.2","1.5.0","1.5.0.rc1","1.5.1","1.5.2","1.6.0","1.6.1","1.6.2","1.6.3","1.7.0","1.7.0.rc1","1.7.1","1.7.2","1.7.3","1.7.4","1.8.0","1.8.0.rc1","1.8.0.rc2","1.8.0.rc3","1.8.1","1.9.0","1.9.0.rc1","1.9.0.rc2","1.9.1","1.9.2","1.9.3"],"database_specific":{"source":"https://github.com/github/advisory-database/blob/main/advisories/github-reviewed/2021/11/GHSA-hwhf-64mh-r662/GHSA-hwhf-64mh-r662.json"}}],"schema_version":"1.9.0","severity":[{"type":"CVSS_V3","score":"CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:N/A:H"}]}