Executive brief
StackStorm st2 is an event-driven automation platform used for incident response and operational workflows. Under specific conditions (Python 3.x with non-UTF-8 locale and Unicode action/rule names), a flaw causes an infinite loop that rapidly consumes all available memory and disk space, leading to complete service unavailability and potential data loss.
Technical details
This vulnerability is a Denial of Service caused by an infinite loop (CWE-835) in the logging component when handling Unicode characters. The issue occurs specifically when Python 3.x is used, the system locale is not UTF-8, and st2 attempts to log Unicode data from action or rule names. The attack vector is network-adjacent (triggering via automation rules or actions), requires no authentication, and can consume all available system resources. An attacker can trigger the condition by creating automation rules or actions with Unicode names. The vulnerability was fixed in version 3.4.1 and affects all versions prior to that release.
Affected products
- StackStorm st2 before 3.4.1
Timeline
- 2021-03-18: disclosed
- 2021: patched: Fixed in version 3.4.1
- 2022-05-24: advisory
- 2023-08-07: other: Advisory withdrawn from GitHub Advisory Database