CVE-2021-32839High· 7.5▾ TwilightStripComments filter contains a regular expression that is vulnerable to ReDOS (Regular Expression Denial of Service)
▾ Twilight zone — High severity, or a signal on a lesser flaw
impact 41.3 · likelihood 0.5 · exploitation 0
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Exploit-prediction probability, daily snapshots since Jul 8.
Disclosure to exploitation, from the record and what we observed since indexing it.
Disclosed via OSV
Last analysed / modified upstream
2.1%
2.1% → 2.3%
The formatter function that strips comments from a SQL contains a regular expression that is vulnerable to ReDoS (Regular Expression Denial of Service). The regular expression may cause exponential backtracking on strings containing many repetitions of '\r\n' in SQL comments.
The issues has been fixed in sqlparse 0.4.2.
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.
This issue was discovered by GitHub team members @erik-krogh and @yoff. It was found using a CodeQL query which identifies inefficient regular expressions. You can see the results of the query on python-sqlparse by following this link.
If you have any questions or comments about this advisory:
sqlparse >= 0.4.0, < 0.4.2Upgrade to a patched release:
sqlparse 0.4.2Connected by shared product, vendor, weakness, or advisory.
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