CVE-2026-23268
Published: 18 March 2026
Summary
CVE-2026-23268 is a high-severity an unspecified weakness vulnerability in Linux Linux Kernel. Its CVSS base score is 7.8 (High).
Operationally, exploitation aligns with the MITRE ATT&CK technique Exploitation for Privilege Escalation (T1068); ranked at the 3.3th percentile by exploit likelihood (below the median); it is not currently listed in the CISA KEV catalog.
The strongest mitigations our analysis identified are NIST 800-53 AC-25 (Reference Monitor) and AC-3 (Access Enforcement).
Deeper analysis
CVE-2026-23268 is a vulnerability in the Linux kernel's AppArmor security module that allows an unprivileged local user to perform privileged policy management operations. Specifically, an attacker can load, replace, or remove AppArmor profiles by opening file descriptors to apparmorfs interfaces and exploiting a confused deputy attack, where the opened file descriptor is passed to a privileged process that is then manipulated into writing to the interface.
The attack requires local access with low privileges (PR:L) and low complexity (AC:L), targeting a privileged process susceptible to manipulation, such as through delegated file descriptor access. Successful exploitation grants full AppArmor policy control, enabling attackers to remove application confinement, cause denial-of-service by blocking executions, bypass unprivileged user namespace restrictions, or chain with other kernel bugs for local privilege escalation. The CVSS v3.1 base score is 7.8 (AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H), reflecting high impact on confidentiality, integrity, and availability.
Mitigation is provided through kernel patches in stable branches, as detailed in the referenced commits (e.g., 0fc63dd9170643d15c25681fca792539e23f4640, 17debf5586020790b5717f96e5e6a3ca5bb961ab). These changes enforce that the task writing to the interface must possess privileges that are a subset of those held by the task that opened it, preventing unconfined processes from delegating access to bypass policy checks. Security practitioners should update to patched kernel versions supporting AppArmor.
EU & UK References
- 🇪🇺 ENISA EUVD: EUVD-2026-12910
Vulnerability details
In the Linux kernel, the following vulnerability has been resolved: apparmor: fix unprivileged local user can do privileged policy management An unprivileged local user can load, replace, and remove profiles by opening the apparmorfs interfaces, via a confused deputy attack,…
more
by passing the opened fd to a privileged process, and getting the privileged process to write to the interface. This does require a privileged target that can be manipulated to do the write for the unprivileged process, but once such access is achieved full policy management is possible and all the possible implications that implies: removing confinement, DoS of system or target applications by denying all execution, by-passing the unprivileged user namespace restriction, to exploiting kernel bugs for a local privilege escalation. The policy management interface can not have its permissions simply changed from 0666 to 0600 because non-root processes need to be able to load policy to different policy namespaces. Instead ensure the task writing the interface has privileges that are a subset of the task that opened the interface. This is already done via policy for confined processes, but unconfined can delegate access to the opened fd, by-passing the usual policy check.
- CWE(s)
Related Threats
MITRE ATT&CK Enterprise TechniquesAI
Why these techniques?
Vulnerability directly enables AppArmor policy manipulation/bypass (impairing defenses) and chaining for local privilege escalation.
CVEs Like This One
Affected Assets
Mitigating Controls
Mitigating Controls (NIST 800-53 r5) AI
Requires enforcement of approved authorizations on apparmorfs interfaces, preventing unprivileged users from loading, replacing, or removing AppArmor profiles via delegated file descriptors.
Enforces least privilege by ensuring tasks writing to policy interfaces hold privileges that are a subset of the opening task, blocking confused deputy attacks.
Mandates a properly implemented reference monitor for AppArmor policy enforcement, ensuring complete mediation and tamper-proof checks on privileged operations.