high7.5

CVE-2021-32839

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

Impact

### 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 [albrecht.andi@gmail.com](mailto:albrecht.andi@gmail.com)

Affected packages

Ecosystem	Package	Affected	Fixed in
pip	`sqlparse`	>= 0.4.0, < 0.4.2	0.4.2

Affected products

Vendor	Product	Affected versions
Sqlparse Project	Sqlparse	from 0.4.0 before 0.4.2

Weakness classification

CWE-400