CVE-2026-80619 in Linux
Summary
by MITRE • 08/28/2026
In the Linux kernel, the following vulnerability has been resolved:
apparmor: fix potential UAF in aa_replace_profiles
The function aa_replace_profiles was accessing udata->size after calling aa_put_loaddata(udata), causing a potential UAF.
Fixed this by saving the size to a local variable before dropping the reference.
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Analysis
by VulDB Data Team • 08/28/2026
The Linux kernel's AppArmor mandatory access control subsystem contains a use-after-free vulnerability within the aa_replace_profiles function, which is responsible for managing profile replacements during security policy updates. This flaw arises from an incorrect ordering of operations in the code path that handles load data structures. Specifically, the implementation accesses the size field of the udata structure after invoking aa_put_loaddata, a routine designed to release references and potentially free memory associated with that structure. By dereferencing a pointer to freed memory, the kernel enters an undefined state where it may read stale or corrupted data, leading to unpredictable behavior such as system crashes, privilege escalation, or information disclosure depending on how the heap is subsequently utilized by other processes.
From a technical perspective, this vulnerability represents a classic use-after-free condition classified under CWE-416 in the Common Weakness Enumeration standard. The root cause lies in the failure to preserve necessary metadata before releasing ownership of the underlying resource. In high-concurrency environments or during rapid policy updates, an attacker with local access could potentially exploit timing windows to manipulate heap allocations and overwrite freed memory regions. This would allow for arbitrary code execution if the overwritten data is later interpreted as executable instructions or control flow pointers by the kernel. The severity is compounded by the fact that AppArmor operates at a privileged level within the operating system, meaning successful exploitation compromises the integrity of the entire host environment rather than just an isolated application sandbox.
The operational impact of this vulnerability extends beyond immediate stability issues to include significant security risks for systems relying on AppArmor for confinement and isolation. If exploited, it could allow a malicious user or compromised process to bypass access controls by corrupting kernel memory structures that govern profile enforcement mechanisms. This undermines the fundamental promise of mandatory access control systems, which rely on strict adherence to defined policies without runtime manipulation via memory corruption techniques. Organizations running Linux distributions with affected kernel versions are exposed to potential remote code execution if combined with other vulnerabilities or local privilege escalation paths, making this a critical issue for enterprise and cloud infrastructure security postures.
Mitigation strategies primarily involve applying the upstream kernel patch that corrects the reference counting logic by storing the size value in a local variable prior to calling aa_put_loaddata. This ensures that all necessary data is captured while the structure remains valid and accessible. Administrators should verify their current kernel version against vendor advisories for Linux distributions such as Ubuntu, Debian, Red Hat Enterprise Linux, or SUSE Linux Enterprise Server, which have likely released updated packages addressing this specific flaw in the AppArmor subsystem. Additionally, keeping systems patched with the latest security updates is essential to prevent exploitation of known memory corruption vulnerabilities that target kernel-space components like mandatory access control modules.