CVE-2021-3749 axios CVE debrief

Who should care

Organizations operating Subnet Solutions Inc. PowerSYSTEM Center in OT/ICS environments, particularly electric utility and critical infrastructure sectors. Security teams responsible for vulnerability management in industrial control systems, network administrators managing PowerSYSTEM Center deployments, and compliance officers tracking CISA ICS advisories should prioritize this patch. The vulnerability's network accessibility and lack of authentication requirements make it particularly concerning for externally accessible or poorly segmented OT networks.

Technical summary

PowerSYSTEM Center versions 2020 v5.21.x and earlier incorporate the Axios HTTP client library, which contains a regular expression complexity vulnerability. The inefficient regex implementation in Axios can be exploited to cause excessive CPU consumption and denial of service when processing maliciously crafted input. This vulnerability is remotely exploitable without authentication (AV:N/AC:L/PR:N/UI:N) and results in high availability impact. The attack surface is primarily through HTTP-based interactions processed by the Axios library within the PowerSYSTEM Center application stack.

Defensive priority

HIGH

Recommended defensive actions

• Update PowerSYSTEM Center to version 2020 Update 22 or later by accessing Settings > Overview > Version within the application, or contact Subnet Solutions Customer Service for assistance
• If immediate patching is not feasible, disable usage of previous UI extensions as a compensating control
• Restrict PowerSYSTEM Center Client Access Server users' ability to access browser F12 Developer Tools to limit visibility of HTTP headers and XSRF-TOKEN manipulation
• Apply network segmentation for OT/ICS environments hosting PowerSYSTEM Center to limit exposure of vulnerable systems
• Monitor for anomalous HTTP request patterns that may indicate attempted regular expression complexity attacks against Axios components

Evidence notes

The vulnerability description is derived from CISA CSAF advisory ICSA-24-277-02, which identifies PowerSYSTEM Center versions <=PSC_2020_v5.21.x as affected. The advisory confirms the product utilizes Axios, which is vulnerable to inefficient regular expression complexity. CVSS 3.1 vector AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H indicates network-accessible, low-complexity attack with no privileges required, resulting in high availability impact. The vendor fix is documented as PowerSYSTEM Center 2020 Update 22.

Sources and references

Methodology and review provenance

AI-assisted synthesis based on stored public vulnerability evidence. System validation, approval state, and publication status do not by themselves establish human review of this revision. PatchSiren helps prioritize defensive review and does not prove exposure or remediation on any system.