SaltStack - Authentication Bypass (CVE-2021-25281)

CVE-2021-25281 is a critical vulnerability in SaltStack Salt before version 3002.5, where the salt-api fails to enforce eauth credentials for the wheel_async client. This flaw allows remote attackers to execute arbitrary wheel modules on the Salt master, potentially leading to full system compromise.

CrowdSec has been tracking this vulnerability and its exploits since 7th of January 2026.

Data from the CrowdSec community indicates that exploitation of CVE-2021-25281 is highly selective and intelligence-driven. Threat actors use advanced reconnaissance and carefully choose their targets, often as part of sophisticated campaigns or advanced persistent threat operations. Data from the CrowdSec community also indicates a gradual decrease in attacks targeting CVE-2021-25281. While still present in the wild, exploitation levels have dropped noticeably week-over-week. This may signal that the vulnerability is becoming less relevant or that defenses are improving fast enough for attackers to lose interest.

Attackers exploit this vulnerability by sending unauthenticated POST requests to the /run endpoint with a JSON body specifying the client parameter as wheel_async, allowing them to bypass authentication and execute arbitrary wheel modules on the Salt master.