CVE-2026-78635 in Privileged Access Client
Summary
by MITRE • 09/09/2026
The Okta Privileged Access client URL handler does not insert an option terminator before appending the target value to the command-line arguments. When a scaleft:// protocol handler link contains a value beginning with a hyphen, the underlying CLI framework interprets it as a command-line flag, causing unintended modification of the SSH client's behavior.
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Analysis
by VulDB Data Team • 09/09/2026
The vulnerability in question resides within the Okta Privileged Access client, specifically affecting its URL handling mechanism for custom protocol schemes such as scaleft://. This component is responsible for parsing incoming links and translating them into executable commands that interact with underlying system utilities, most notably SSH clients used to establish secure shell sessions. The core technical flaw stems from a failure in input sanitization during the construction of command-line arguments. When the client receives a URL containing parameters or target values, it appends these values directly to the argument list without verifying whether they begin with characters that hold special meaning in command-line parsing contexts. Specifically, the application fails to insert an option terminator, commonly represented as double hyphens (--), before appending user-supplied data. This omission creates a critical gap where untrusted input is treated as executable code or configuration flags by the downstream CLI framework.
In standard Unix-like operating systems and many Windows command-line interfaces, arguments beginning with a single hyphen are interpreted as options or flags rather than positional parameters. By not inserting an option terminator before appending these values, the application allows attackers to inject arbitrary flags into the SSH client's execution context. For instance, if a malicious scaleft:// link contains a parameter starting with a hyphen, such as -o ProxyCommand=malicious_script.sh, the underlying CLI framework will parse this string not as part of the target host or username but as an instruction to modify how the SSH session is established. This behavior bypasses normal validation checks because the application assumes that any value passed via URL parameters is safe for direct inclusion in the command line without further scrutiny regarding its syntactic structure relative to CLI parsing rules.
The operational impact of this vulnerability is significant, particularly given the privileged nature of the Okta Privileged Access platform which manages access to critical infrastructure and sensitive systems. An attacker who can trick a user into clicking on a crafted URL or automate the generation of such links could achieve arbitrary command execution through the SSH client's configuration options. This might involve redirecting traffic through a malicious proxy, modifying authentication methods to bypass security controls, or executing scripts during session initialization. Since Okta serves as an identity provider for many enterprises, compromising this vector allows lateral movement within internal networks by exploiting trusted administrative tools. The severity is amplified because the vulnerability leverages legitimate system utilities rather than introducing new code paths that might be more easily detected by endpoint protection solutions.
From a classification perspective, this issue aligns with CWE-78 Improper Neutralization of Special Elements used in an OS Command, commonly known as Operating System Command Injection. The root cause is identified as CWE-20 Incorrect Input Validation, where the application fails to properly sanitize or validate input data before using it in command construction. In terms of offensive security frameworks, this vulnerability facilitates techniques associated with ATT&CK T1059 Command and Scripting Interpreter, specifically through argument injection that alters program behavior without executing new binaries directly. It also touches upon lateral movement vectors by manipulating the SSH client to connect to unauthorized destinations or use compromised authentication mechanisms.
Mitigation strategies should focus on both immediate remediation and long-term architectural improvements. The primary fix involves modifying the URL handler logic to explicitly insert an option terminator before appending any user-supplied values to command-line arguments, ensuring that all subsequent parameters are treated as positional data rather than flags. Additionally, developers should implement strict allow-listing for acceptable characters in URL parameters intended for CLI consumption and avoid passing raw user input directly into system commands whenever possible. Input validation must be enforced at multiple layers, including the web application layer where URLs are generated or accepted, to prevent malicious payloads from reaching the client-side handler in the first place. Security teams should also monitor for unusual SSH connection patterns originating from Okta clients as a detection mechanism while patches are being deployed across affected environments.