CWE-284: Improper Access Control

The product does not restrict or incorrectly restricts access to a resource from an unauthorized actor.

Access control involves the use of several protection mechanisms such as: Authentication (proving the identity of an actor) Authorization (ensuring that a given actor can access a resource), and Accountability (tracking of activities that were performed) When any mechanism is not applied or otherwise fails, attackers can compromise the security of the product by gaining privileges, reading sensitive information, executing commands, evading detection, etc. There are two distinct behaviors that can introduce access control weaknesses: Specification: incorrect privileges, permissions, ownership, etc. are explicitly specified for either the user or the resource (for example, setting a password file to be world-writable, or giving administrator capabilities to a guest user). This action could be performed by the program or the administrator. Enforcement: the mechanism contains errors that prevent it from properly enforcing the specified access control requirements (e.g., allowing the user to specify their own privileges, or allowing a syntactically-incorrect ACL to produce insecure settings). This problem occurs within the program itself, in that it does not actually enforce the intended security policy that the administrator specifies.

Consequences

• Other: Varies by Context

How to prevent it

• 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.

Recent advisories

• GHSA-8g5g-mxqh-grgj — Vite: `server.fs.deny` bypassed with queries
• GHSA-rq7h-c2jc-7f22 — Vite: Files outside `server.fs.allow` could be served when project paths match system paths on non-Windows machine
• GHSA-pjr3-86v4-5p7w — Vikunja: Explicit lower-permission share on a sub-project is silently overridden by an inherited parent permission (broken access control / privilege-management regression in v2.6.0)
• GHSA-hmp2-4m7g-22cv — Backstage: Scaffolder action input authorization bypass
• GHSA-fx49-4h83-wjv9 — Payload didn't enforce field-level password update restrictions
• GHSA-fgmf-7rf8-m6vf — ZITADEL: Actions V1 sandbox escape: host file read via require()
• GHSA-6rh5-qq4q-97xh — vm2: NodeVM builtin denylist bypass via fs/promises despite -fs, allowing host filesystem writes
• GHSA-8686-vhfx-7r3j — vm2: NodeVM node:-prefixed negative builtin deny bypass exposes child_process
• CVE-2026-81963 — Improper link resolution before file access ('link following') in Windows Update Stack allows an authorized attacker to elevate privileges locally.
• EEF-CVE-2026-82745 — ETS and Mnesia data layers overwrite an existing record on create instead of enforcing primary-key uniqueness
• GHSA-gcx9-497g-6cp6 — Apache Tomcat has an Improper Access Control, Incorrect Authorization vulnerability
• GHSA-6g6r-q6gw-w8fg — PraisonAI has a Browser Server WebSocket origin validation bypass via unanchored regex (patch bypass of CVE-2026-40289 / GHSA-8x8f-54wf-vv92)
• GHSA-72r2-7mfr-5xr9 — NLTK: FileSystemPathPointer.open() sandbox check is dead code — arbitrary file read via file:// protocol
• GO-2026-6319 — Incus has a project restriction bypass in instance copy across projects
• GHSA-64f3-v33m-w89f — Incus has a project restriction bypass for custom volume copy across projects

All advisories for CWE-284