Cisco Secure Web Appliance Authentication Bypass Vulnerability
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. Cisco has released software updates that address this vulnerability. There are no workarounds that address this vulnerability. This advisory is available at the following link: https://sec.cloudapps.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-wsa-auth-bypass-6YZkTQhd Security Impact Rating: Medium CVE: CVE-2026-20152
CSIRTS triage
- What
- This vulnerability allows an unauthenticated remote attacker to bypass authentication policy requirements.
- Who is affected
- Deployments of Cisco Secure Web Appliance are affected.
- Urgency
- Remediation is urgent due to the potential for unauthorized access.
- Action
- Update to the latest version of Cisco AsyncOS Software to address this vulnerability.
AI-assisted analysis generated from the source advisory — verify against the original.
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Details
Exploitation outlook
EPSS (FIRST.org) estimates each CVE’s probability of exploitation in the next 30 days — here is the CSIRTS.com read on those numbers.
- Low exploitation riskCVE-2026-201520.30% 30-day exploitation probability — currently an unlikely target, but scores change as exploit code circulates. Riskier than 22% of all scored CVEs.
Referenced CVEs
| CVE | CSIRTS overview | External |
|---|---|---|
| CVE-2026-20152 | coverage & exploitation status | NVD · CVE.org |
Recent advisories for Cisco Secure Web
A cluster of recent advisories against the same product widens the attack surface — attackers routinely chain freshly published CVEs on one product, so review these together.
- critical2025-042: Critical Vulnerability in Cisco Secure Email and Web Managercert-eu · 2025-12-18
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