CWE-268 Base Draft High likelihood

Privilege Chaining

Privilege chaining occurs when an attacker combines two separate permissions or capabilities, neither of which is dangerous on its own, to perform a harmful action that neither permission should…

Definition

What is CWE-268?

Privilege chaining occurs when an attacker combines two separate permissions or capabilities, neither of which is dangerous on its own, to perform a harmful action that neither permission should individually allow.

This vulnerability is like a security bypass puzzle. A system might correctly enforce that a user cannot directly delete a file or directly write to a system directory. However, if the user can first move a file into that protected directory (using one permission) and then delete any file they own there (using a second permission), they have effectively achieved an unauthorized deletion. The core failure is that the system's security checks evaluate each privilege in isolation, missing the dangerous sequence they enable when used together. To prevent this, developers must design authorization checks that consider context and history, not just the immediate action. This involves analyzing how privileges can interact over a session or transaction. Implementing mandatory access control (MAC), logging and monitoring for unusual privilege sequences, and adhering to the principle of least privilege are key defenses. Always ask: 'Could these two allowed actions be combined to achieve something we explicitly forbid?'

Real-world impact

Real-world CVEs caused by CWE-268

CVE-2005-1736

Chaining of user rights.
CVE-2002-1772

Gain certain rights via privilege chaining in alternate channel.
CVE-2005-1973

Application is allowed to assign extra permissions to itself.
CVE-2003-0640

"operator" user can overwrite usernames and passwords to gain admin privileges.

How attackers exploit it

Step-by-step attacker path

1
Identify a code path that handles untrusted input without validation.
2
Craft a payload that exercises the unsafe behavior — injection, traversal, overflow, or logic abuse.
3
Deliver the payload through a normal request and observe the application's reaction.
4
Iterate until the response leaks data, executes attacker code, or escalates privileges.

Vulnerable code example

Vulnerable Java

This code allows someone with the role of "ADMIN" or "OPERATOR" to reset a user's password. The role of "OPERATOR" is intended to have less privileges than an "ADMIN", but still be able to help users with small issues such as forgotten passwords.

Vulnerable Java

public enum Roles {
  	ADMIN,OPERATOR,USER,GUEST
  }
  public void resetPassword(User requestingUser, User user, String password ){
  		if(isAuthenticated(requestingUser)){
  				switch(requestingUser.role){
  						case GUEST:
  							System.out.println("You are not authorized to perform this command");
  							break;
  						case USER:
  							System.out.println("You are not authorized to perform this command");
  							break;
  						default:
  							setPassword(user,password);
  							break;
  						}
  				}
  		else{
  			System.out.println("You must be logged in to perform this command");
  		}
  }

Secure code example

Secure pseudo

// Validate, sanitize, or use a safe API before reaching the sink.
function handleRequest(input) {
  const safe = validateAndEscape(input);
  return executeWithGuards(safe);
}

What changed: the unsafe sink is replaced (or the input is validated/escaped) so the same payload no longer triggers the weakness.

Prevention checklist

How to prevent CWE-268

Architecture and Design Consider following the principle of separation of privilege. Require multiple conditions to be met before permitting access to a system resource.
Architecture and Design / Operation Very carefully manage the setting, management, and handling of privileges. Explicitly manage trust zones in the software.
Architecture and Design / Operation Run your code using the lowest privileges that are required to accomplish the necessary tasks [REF-76]. If possible, create isolated accounts with limited privileges that are only used for a single task. That way, a successful attack will not immediately give the attacker access to the rest of the software or its environment. For example, database applications rarely need to run as the database administrator, especially in day-to-day operations.

Detection signals

How to detect CWE-268

SAST High

Run static analysis (SAST) on the codebase looking for the unsafe pattern in the data flow.

DAST Moderate

Run dynamic application security testing against the live endpoint.

Runtime Moderate

Watch runtime logs for unusual exception traces, malformed input, or authorization bypass attempts.

Code review Moderate

Code review: flag any new code that handles input from this surface without using the validated framework helpers.

CWE-268

Don't catalog this weakness. Prove it's reachable.

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Frequently asked questions

What is CWE-268?

How serious is CWE-268?

MITRE rates the likelihood of exploit as High — this weakness is actively exploited in the wild and should be prioritized for remediation.

What languages or platforms are affected by CWE-268?

MITRE has not specified affected platforms for this CWE — it can apply across most application stacks.

How can I prevent CWE-268?

Consider following the principle of separation of privilege. Require multiple conditions to be met before permitting access to a system resource. Very carefully manage the setting, management, and handling of privileges. Explicitly manage trust zones in the software.

How does Plexicus detect and fix CWE-268?

Plexicus's SAST engine matches the data-flow signature for CWE-268 on every commit. When a match is found, our Codex Remedium agent opens a fix PR with the corrected code, tests, and a one-line summary for the reviewer.

Where can I learn more about CWE-268?

MITRE publishes the canonical definition at https://cwe.mitre.org/data/definitions/268.html. You can also reference OWASP and NIST documentation for adjacent guidance.

Related weaknesses

Weaknesses related to CWE-268

CWE-269 Parent

Privilege Chaining

What is CWE-268?

Real-world CVEs caused by CWE-268

Step-by-step attacker path

Vulnerable Java

Secure pseudo

How to prevent CWE-268

How to detect CWE-268

Don't catalog this weakness. Prove it's reachable.

Frequently asked questions

Weaknesses related to CWE-268

Improper Privilege Management

Execution with Unnecessary Privileges

Incorrect Privilege Assignment

Privilege Defined With Unsafe Actions

Privilege Context Switching Error

Privilege Dropping / Lowering Errors

Improper Handling of Insufficient Privileges

Incorrect Use of Privileged APIs

Further reading

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Sample evidence handover

Server-Side Request Forgery in `webhooks/receiver`