catch deeply nested CQL2 text filters#576
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The cql2-text parser (ANTLR) and the subsequent tree visit both recurse with the nesting depth of the expression, and parse() only caught ParseCancellationException. A filter with a few thousand nested parentheses in the (uncapped) `filter` query parameter therefore overflowed the stack and crashed the request thread. The cql2-json path is already bounded by Jackson's nesting limit. Add a complexity guard before parsing: reject filters over a maximum length and those nesting parentheses beyond a maximum depth (measured outside string literals, so parentheses in a literal value do not count). Also catch StackOverflowError at the parse boundary as a safety net and surface it as a CqlParseException instead of a crash. Adds CqlTextParserComplexitySpec.
azahnen
approved these changes
Jul 20, 2026
azahnen
enabled auto-merge (squash)
July 20, 2026 17:04
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The cql2-text parser (ANTLR) and the subsequent tree visit both recurse with the nesting depth of the expression, and parse() only caught ParseCancellationException. A filter with a few thousand nested parentheses in the (uncapped)
filterquery parameter therefore overflowed the stack and crashed the request thread. The cql2-json path is already bounded by Jackson's nesting limit.Add a complexity guard before parsing: reject filters over a maximum length and those nesting parentheses beyond a maximum depth (measured outside string literals, so parentheses in a literal value do not count). Also catch StackOverflowError at the parse boundary as a safety net and surface it as a CqlParseException instead of a crash.
Adds CqlTextParserComplexitySpec.