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CVE-2021-32839 High

StripComments filter contains a regular expression that is vulnerable to ReDOS (Regular Expression Denial of Service)

### Impact The 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. ### Patches The issues has been fixed in sqlparse 0.4.2. ### Workarounds Only 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. ### References This 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/). ### For more information If you have any questions or comments about this advisory: * Open an issue in [sqlparse issue tracker](https://github.com/andialbrecht/sqlparse/issues) * Email us at [[email protected]](mailto:[email protected])

Exploit probability 2.3%
Published September 10, 2021
Required by Not available
Last source change July 8, 2026

02 / AFFECTED SOFTWARE

Affected packages

Unknown Unknown

2 explicit affected versions

PyPI sqlparse

2 explicit affected versions

PyPI sqlparse

2 explicit affected versions

03 / CONNECTIONS

Connected vulnerabilities

04 / EVIDENCE

Source records

Open Source Vulnerabilities GHSA-p5w8-wqhj-9hhf

### Impact The 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. ### Patches The issues has been fixed in sqlparse 0.4.2. ### Workarounds Only 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. ### References This 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/). ### For more information If you have any questions or comments about this advisory: * Open an issue in [sqlparse issue tracker](https://github.com/andialbrecht/sqlparse/issues) * Email us at [[email protected]](mailto:[email protected])

View original source
Open Source Vulnerabilities PYSEC-2021-333

sqlparse is a non-validating SQL parser module for Python. In sqlparse versions 0.4.0 and 0.4.1 there is a regular Expression Denial of Service in sqlparse vulnerability. The regular expression may cause exponential backtracking on strings containing many repetitions of '\r\n' in SQL comments. Only 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. The issues has been fixed in sqlparse 0.4.2.

View original source
Open Source Vulnerabilities CVE-2021-32839

sqlparse is a non-validating SQL parser module for Python. In sqlparse versions 0.4.0 and 0.4.1 there is a regular Expression Denial of Service in sqlparse vulnerability. The regular expression may cause exponential backtracking on strings containing many repetitions of '\r\n' in SQL comments. Only 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. The issues has been fixed in sqlparse 0.4.2.

View original source

05 / REFERENCES

Further evidence