Uncontrolled Resource Consumption (CWE-400 / CWE-1333) in regex search query predicates (such as RegexProjectPredicate, RegexRefPredicate, RegexPathPredicate, and sibling predicates) and REST regex filter endpoints (RegexListSearcher /pr…

Overview

Uncontrolled Resource Consumption (CWE-400 / CWE-1333) in regex search query predicates (such as RegexProjectPredicate, RegexRefPredicate, RegexPathPredicate, and sibling predicates) and REST regex filter endpoints (RegexListSearcher /projects/?r= and RefFilter /projects/{project}/branches/?r=) in Gerrit Code Review versions 2.1.6 through 3.12.9, 3.13.0 through 3.13.8, and 3.14.0 through 3.14.2 allows an unauthenticated remote attacker (or an authenticated user if anonymous read access is disabled) to cause a denial of service (CPU starvation and JVM heap exhaustion / OutOfMemoryError) via crafted search queries or REST API requests containing regular expressions with large counted repetitions or exponential DFA determinization patterns. Because the user-supplied regular expression is compiled into an unbounded dk.brics.automaton instance (new RegExp(re).toAutomaton()) on the request thread prior to index evaluation or access control visibility filtering, trivial queries can exhaust JVM heap or pin request threads regardless of heap size. This issue is fixed in Gerrit Code Review versions 3.12.10, 3.13.9, and 3.14.3.

Remediation

Refer to the linked advisories for vendor-supplied fixes and affected version ranges.