CWE-279 Variant Draft

Incorrect Execution-Assigned Permissions

This vulnerability occurs when a running application incorrectly changes an object's access permissions, overriding the security settings that a user or administrator intentionally configured.

Definition

What is CWE-279?

This vulnerability occurs when a running application incorrectly changes an object's access permissions, overriding the security settings that a user or administrator intentionally configured.
This flaw typically happens during an application's runtime operations, such as when it creates temporary files, spawns new processes, or modifies system resources. Instead of respecting the principle of least privilege, the software assigns broader permissions—like making a file world-writable or granting excessive privileges to a process—than what was originally intended. This creates a window of opportunity where unauthorized users or processes can read, modify, or execute sensitive resources. To prevent this, developers must ensure that permission assignments are explicit, validated, and adhere strictly to the user-specified security policy throughout the entire lifecycle of an object. Code should avoid implicit or default permission settings during execution, and security-critical functions must consistently check and apply the correct, minimal permissions required for the task.
Real-world impact

Real-world CVEs caused by CWE-279

How attackers exploit it

Step-by-step attacker path

  1. 1

    Identify a code path that handles untrusted input without validation.

  2. 2

    Craft a payload that exercises the unsafe behavior — injection, traversal, overflow, or logic abuse.

  3. 3

    Deliver the payload through a normal request and observe the application's reaction.

  4. 4

    Iterate until the response leaks data, executes attacker code, or escalates privileges.

Vulnerable code example

Vulnerable pseudo

MITRE has not published a code example for this CWE. The pattern below is illustrative — see Resources for canonical references.

Vulnerable pseudo 
// Example pattern — see MITRE for the canonical references.
function handleRequest(input) {
  // Untrusted input flows directly into the sensitive sink.
  return executeUnsafe(input);
}
Secure code example

Secure pseudo

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-279

  • Architecture and Design / Operation Very carefully manage the setting, management, and handling of privileges. Explicitly manage trust zones in the software.
  • Architecture and Design Compartmentalize the system to have "safe" areas where trust boundaries can be unambiguously drawn. Do not allow sensitive data to go outside of the trust boundary and always be careful when interfacing with a compartment outside of the safe area. Ensure that appropriate compartmentalization is built into the system design, and the compartmentalization allows for and reinforces privilege separation functionality. Architects and designers should rely on the principle of least privilege to decide the appropriate time to use privileges and the time to drop privileges.
Detection signals

How to detect CWE-279

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.

Plexicus auto-fix

Plexicus auto-detects CWE-279 and opens a fix PR in under 60 seconds.

Codex Remedium scans every commit, identifies this exact weakness, and ships a reviewer-ready pull request with the patch. No tickets. No hand-offs.

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Frequently asked questions

Frequently asked questions

What is CWE-279?

This vulnerability occurs when a running application incorrectly changes an object's access permissions, overriding the security settings that a user or administrator intentionally configured.

How serious is CWE-279?

MITRE has not published a likelihood-of-exploit rating for this weakness. Treat it as medium-impact until your threat model proves otherwise.

What languages or platforms are affected by CWE-279?

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

How can I prevent CWE-279?

Very carefully manage the setting, management, and handling of privileges. Explicitly manage trust zones in the software. Compartmentalize the system to have "safe" areas where trust boundaries can be unambiguously drawn. Do not allow sensitive data to go outside of the trust boundary and always be careful when interfacing with a compartment outside of the safe area. Ensure that appropriate compartmentalization is built into the system design, and the compartmentalization allows for and…

How does Plexicus detect and fix CWE-279?

Plexicus's SAST engine matches the data-flow signature for CWE-279 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-279?

MITRE publishes the canonical definition at https://cwe.mitre.org/data/definitions/279.html. You can also reference OWASP and NIST documentation for adjacent guidance.

Related weaknesses

Weaknesses related to CWE-279

CWE-732 Parent

Incorrect Permission Assignment for Critical Resource

This vulnerability occurs when a system grants overly permissive access to a sensitive resource, allowing unauthorized users or processes…

CWE-1004 Sibling

Sensitive Cookie Without 'HttpOnly' Flag

This vulnerability occurs when an application stores sensitive data in a cookie but fails to set the 'HttpOnly' flag, leaving the cookie…

CWE-276 Sibling

Incorrect Default Permissions

This vulnerability occurs when software installation scripts set overly permissive file or directory access rights by default. Instead of…

CWE-277 Sibling

Insecure Inherited Permissions

This vulnerability occurs when an application sets default file or directory permissions that are too permissive, and these insecure…

CWE-278 Sibling

Insecure Preserved Inherited Permissions

This vulnerability occurs when a software product copies or extracts files while unintentionally preserving insecure permissions from…

CWE-281 Sibling

Improper Preservation of Permissions

This vulnerability occurs when a system fails to correctly maintain file or object permissions during operations like copying, sharing, or…

CWE-766 Sibling

Critical Data Element Declared Public

This vulnerability occurs when a critical piece of data—like a variable, field, or class member—is mistakenly declared as public when it…

Resources

Further reading

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