CVE-2026-20152
Received Received - Intake
Authentication Bypass in Cisco AsyncOS via Improper Input Validation

Publication date: 2026-04-15

Last updated on: 2026-04-15

Assigner: Cisco Systems, Inc.

Description
A vulnerability in the authentication service feature of Cisco AsyncOS Software for Cisco Secure Web Appliance could allow an unauthenticated, remote attacker to bypass authentication policy requirements. This vulnerability is due to improper validation of user-supplied authentication input in HTTP requests. An attacker could exploit this vulnerability by sending HTTP requests that contain specific authentication requests to an affected device. A successful exploit could allow the attacker to bypass policy enforcement on the device. There is no direct impact to the Cisco Secure Web Appliance. However, as a result of exploiting this vulnerability, an attacker could send HTTP requests that should be restricted through the device.
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Meta Information
Published
2026-04-15
Last Modified
2026-04-15
Generated
2026-06-16
AI Q&A
2026-04-15
EPSS Evaluated
2026-06-15
NVD
CVE-2026-20152
EUVD
EUVD-2026-22964
Affected Vendors & Products
Showing 3 associated CPEs
Vendor Product Version / Range
cisco asyncos to 15.2 (exc)
cisco secure_web_appliance *
cisco asyncos *
Helpful Resources
Exploitability
CWE
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KEV
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CWE ID Description
CWE-305 The authentication algorithm is sound, but the implemented mechanism can be bypassed as the result of a separate weakness that is primary to the authentication error.
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Executive Summary

This vulnerability exists in the authentication service feature of Cisco AsyncOS Software for Cisco Secure Web Appliance. It allows an unauthenticated, remote attacker to bypass authentication policy requirements by exploiting improper validation of user-supplied authentication input in HTTP requests.

An attacker can send specially crafted HTTP requests containing specific authentication requests to the affected device. If successful, the attacker can bypass the device's policy enforcement.

Impact Analysis

Exploiting this vulnerability could allow an attacker to bypass authentication policies and send HTTP requests that should be restricted by the Cisco Secure Web Appliance.

While there is no direct impact to the device itself, the attacker could potentially access or send unauthorized HTTP requests that the device is supposed to block.

Compliance Impact

This vulnerability allows an unauthenticated, remote attacker to bypass authentication policy requirements on Cisco Secure Web Appliance devices, potentially enabling restricted HTTP requests to pass through the appliance.

While there is no direct impact on the device itself beyond the authentication bypass, the ability to circumvent policy enforcement could lead to unauthorized access or actions that may affect the integrity of protected data or systems.

Such unauthorized access or policy bypass could have implications for compliance with standards and regulations like GDPR or HIPAA, which require strict access controls and protection of sensitive data.

However, the provided information does not explicitly detail the compliance impact or any direct linkage to these regulations.

Detection Guidance

There is no specific information provided about detection methods or commands to identify this vulnerability on your network or system.

Mitigation Strategies

Cisco strongly recommends upgrading to fixed software releases to remediate this issue.

  • Upgrade Cisco AsyncOS to version 15.2.5-013 or later.
  • Ensure device compatibility and memory requirements before upgrading.
  • Obtain fixed software through authorized channels or Cisco TAC if necessary.
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