SB2026030524 - SSH partial private key authentication bypass in Cisco ASA
Published: March 5, 2026
Security Bulletin ID
SB2026030524
Severity
Medium
Patch available
YES
Number of vulnerabilities
1
Exploitation vector
Remote access
Highest impact
Data manipulation
Breakdown by Severity
- Low
- Medium
- High
- Critical
Description
This security bulletin contains information about 1 security vulnerability.
1) Improper neutralization of special elements (CVE-ID: CVE-2026-20009)
The vulnerability allows a remote attacker to impersonate other users.
The vulnerability exists due to insufficient validation of user input during the SSH authentication phase in the implementation of the proprietary SSH stack with SSH key-based authentication. A remote attacker with knowledge of username and the associated public key can submit specially crafted input during SSH authentication to an affected device and log in to the device as a specific user without the private SSH key of that user.
Remediation
Install update from vendor's website.