Quick answers
- Is CVE-2021-28667 exploited in the wild?
- No. Junglewise Threat Intelligence has no report of CVE-2021-28667 being exploited in the wild.
- How severe is CVE-2021-28667?
- Low severity, with a CVSS score of 3.1, published 24 May 2022.
- Which products and versions are affected?
- st2client (PyPI) ECOSYSTEM:introduced=0,fixed=3.4.1; StackStorm St2 before 3.4.1.
- Is there a fix for CVE-2021-28667?
- Yes. st2client (PyPI): upgrade to 3.4.1 or later. Junglewise finds every place you run it, drafts the upgrade and applies it once you approve.
- How is CVE-2021-28667 attacked?
- It is attacked over the network.
- Am I affected by CVE-2021-28667?
- Check whether you run st2client (PyPI) or StackStorm St2 at an affected version. Junglewise does that check for you around the clock: connect your code, cloud and domains, and it matches new vulnerabilities like this one against what you actually run and tells you when one reaches you.
How to fix
- st2client (PyPI): upgrade to 3.4.1 or later
pip install "st2client>=3.4.1"
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
Identifiers
- CVE-2021-28667
- GHSA-39mj-fpg2-3jrg
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- 2023-08-07: other: Advisory withdrawn from GitHub Advisory Database