{"id":"CVE-2021-32839","aliases":["GHSA-p5w8-wqhj-9hhf","PYSEC-2021-333"],"url":"https://o3.security/vulnerability/CVE-2021-32839","summary":"StripComments filter contains a regular expression that is vulnerable to ReDOS (Regular Expression Denial of Service)","details":"### Impact\nThe formatter function that strips comments from a SQL contains a regular expression that is vulnerable to [ReDoS](https://owasp.org/www-community/attacks/Regular_expression_Denial_of_Service_-_ReDoS) (Regular Expression Denial of Service). The regular expression may cause exponential backtracking on strings containing many repetitions of '\\r\\n' in SQL comments.\n\n### Patches\nThe issues has been fixed in sqlparse 0.4.2.\n\n### Workarounds\nOnly the formatting feature that removes comments from SQL statements is affected by this regular expression. As a workaround don't use the `sqlformat.format` function with keyword `strip_comments=True` or the `--strip-comments` command line flag when using the `sqlformat` command line tool.\n\n### References\nThis issue was discovered by GitHub team members @erik-krogh and @yoff. It was found using a [CodeQL](https://codeql.github.com/) query which identifies inefficient regular expressions. You can see the results of the query on python-sqlparse by following [this link](https://lgtm.com/query/2223658096471222354/). \n\n### For more information\nIf you have any questions or comments about this advisory:\n* Open an issue in [sqlparse issue tracker](https://github.com/andialbrecht/sqlparse/issues)\n* Email us at [albrecht.andi@gmail.com](mailto:albrecht.andi@gmail.com)","published":"2021-09-20T17:15:09.067Z","modified":"2026-07-15T07:36:26.641747Z","cvss":{"score":7.5,"severity":"HIGH","vector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H"},"epss":{"score":0.02339,"percentile":0.82502,"asOf":"2026-09-08"},"cisaKev":null,"exploitsKnown":0,"affectedPackages":[{"ecosystem":"PyPI","name":"sqlparse","fixedVersion":"0.4.2"}],"fix":{"url":"https://github.com/andialbrecht/sqlparse/commit/8238a9e450ed1524e40cb3a8b0b3c00606903aeb","label":"andialbrecht/sqlparse@8238a9e"},"references":[{"type":"WEB","url":"https://lists.debian.org/debian-lts-announce/2024/12/msg00022.html"},{"type":"ADVISORY","url":"https://github.com/andialbrecht/sqlparse/security/advisories/GHSA-p5w8-wqhj-9hhf"},{"type":"FIX","url":"https://github.com/andialbrecht/sqlparse/commit/8238a9e450ed1524e40cb3a8b0b3c00606903aeb"},{"type":"ADVISORY","url":"https://nvd.nist.gov/vuln/detail/CVE-2021-32839"},{"type":"PACKAGE","url":"https://github.com/andialbrecht/sqlparse"},{"type":"WEB","url":"https://github.com/pypa/advisory-database/tree/main/vulns/sqlparse/PYSEC-2021-333.yaml"},{"type":"ADVISORY","url":"https://securitylab.github.com/advisories/GHSL-2021-107-andialbrecht-sqlparse"}],"provenance":{"sources":["OSV.dev","FIRST.org (EPSS)"],"lastVerified":"2026-07-15T07:36:26.641747Z"}}