Full Report
Cisco has patched several critical and high-severity vulnerabilities, including an Integrated Management Controller (IMC) authentication bypass that enables attackers to gain Admin access. [...]
Analysis Summary
# Vulnerability: Cisco IMC Authentication Bypass (Admin Access)
## CVE Details
- **CVE ID:** CVE-2026-20093
- **CVSS Score:** 9.8 (Critical)
- **CWE:** Incorrect Handling of Password Change Requests (CWE-287 Instance)
## Affected Systems
- **Products:** Cisco Integrated Management Controller (IMC / CIMC) embedded on:
- UCS C-Series Rack Servers
- UCS E-Series Modular Servers
- **Versions:** Vulnerable prior to the release of the April 2026 security updates. (Users should consult the Cisco Advisory for specific fixed release versions per hardware platform).
- **Configurations:** Systems with the Web-based User Interface (WebUI) or XML API interfaces exposed.
## Vulnerability Description
A critical flaw exists in the password change functionality of the Cisco Integrated Management Controller. The issue stems from the incorrect handling of HTTP password change requests. An unauthenticated remote attacker can send a specially crafted HTTP request to the management interface to bypass authentication mechanisms. This allows the attacker to unilaterally change the password of any existing user, including those with Administrative privileges, thereby gaining full control over the out-of-band management of the server.
## Exploitation
- **Status:** Not exploited (No evidence of in-the-wild exploitation at the time of reporting).
- **Complexity:** Low
- **Attack Vector:** Network (Remote)
## Impact
- **Confidentiality:** High (Full access to management data and server configurations).
- **Integrity:** High (Ability to modify any user password and system settings).
- **Availability:** High (Attacker can lock out legitimate admins or power off/reset the physical host).
## Remediation
### Patches
Cisco has released software updates to address this vulnerability. Customers are "strongly recommended" to upgrade to the fixed software versions immediately.
- Refer to the [Cisco Security Advisory](https://sec[.]cloudapps[.]cisco[.]com/security/center/content/CiscoSecurityAdvisory/cisco-sa-cimc-auth-bypass-AgG2BxTn) for specific firmware version mapping.
### Workarounds
- **None:** There are no workarounds or temporary mitigations available for this vulnerability. Patching is the only definitive resolution.
## Detection
- **Indicators of Compromise:** Monitor for unauthorized or unexpected password change events in the Cisco IMC audit logs.
- **Detection methods and tools:** Audit administrative account access for logins from unusual source IP addresses. Ensure Cisco IMC interfaces are placed on isolated management networks (VLANs) not accessible from the public internet.
## References
- **Vendor Advisory:** hxxps[:]//sec[.]cloudapps[.]cisco[.]com/security/center/content/CiscoSecurityAdvisory/cisco-sa-cimc-auth-bypass-AgG2BxTn
- **NVD Entry:** hxxps[:]//nvd[.]nist[.]gov/vuln/detail/CVE-2026-20093
- **Related News:** hxxps[:]//www[.]bleepingcomputer[.]com/news/security/critical-cisco-imc-auth-bypass-gives-attackers-admin-access/