CVE-2026-53113: Linux ath11k WiFi Driver Memory Leak

Technical summary

CVE-2026-53113 is a memory leak (CWE-401) in the ath11k WiFi driver's beacon template initialization routines. The functions ath11k_mac_setup_bcn_tmpl_ema() and ath11k_mac_setup_bcn_tmpl_mbssid() allocate memory for beacon template structures but fail to deallocate that memory when error conditions occur during parameter setup. The vulnerability arises from incomplete error handling paths that do not mirror the cleanup logic present in normal execution flows. The issue was identified through static analysis and code review; the fix implements unified exit paths with proper resource cleanup.

Business impact

Organizations operating WiFi infrastructure using affected Linux kernels—including access points, mesh routers, and edge computing devices—may experience gradual memory exhaustion leading to system instability or service interruption. In environments where kernel memory pressure triggers OOM (out-of-memory) events, legitimate network services can be terminated unexpectedly. This is particularly concerning in unattended or remotely managed deployments where frequent reboots are disruptive. The vulnerability requires local privilege to trigger reliably, reducing risk for typical public WiFi scenarios but increasing risk in shared hosting, multi-tenant edge environments, or scenarios where guest VLANs have kernel module access.

Affected systems

The Linux kernel is affected. The vulnerability is specific to the ath11k WiFi driver, which is used in various WiFi chipsets and devices. Systems running Linux kernels with the vulnerable ath11k code are at risk, particularly: access points, routers, mesh network nodes, embedded Linux devices with WiFi, and any system where the ath11k driver is compiled and in use. The vulnerability requires local privilege (CWE-401 does not typically assume remote code execution as a prerequisite), so the attack surface is limited to local users or authenticated services on the affected system.

Exploitability

Exploitability is low to moderate. The vulnerability requires local access and some level of privilege to invoke the affected beacon template functions repeatedly or under error conditions. It is not remotely exploitable without first compromising local execution context. An attacker with local user privileges could potentially trigger the memory leak by cycling wireless configurations or causing deliberate setup errors. However, this is not a code execution vulnerability; the impact is limited to denial of service through resource exhaustion. No public exploit code is known, and the CVSS 5.5 (MEDIUM) score reflects the local-only attack vector and availability-only impact.

Remediation

Update the Linux kernel to a patched version that includes the fix for the ath11k beacon template memory leak. The fix involves implementing unified exit paths with proper cleanup handlers in the affected functions. Verify the specific patched kernel version against your distribution and vendor security advisories, as patch availability and version numbers vary by Linux distribution. For systems where kernel updates cannot be immediately deployed, restrict local user privileges or disable the ath11k WiFi driver if an alternative driver is available, though this may impact wireless functionality.

Patch guidance

Monitor your Linux distribution's security advisories and kernel update repositories for patches addressing CVE-2026-53113. The kernel should be rebuilt with the corrected ath11k driver code. Most major distributions (Red Hat, Debian, Ubuntu, etc.) will backport this fix to supported kernel versions. When updating, ensure the kernel changelog specifically mentions the resolution of the ath11k beacon template memory leak fix. Test the patched kernel in a non-production environment first, particularly if the system is running WiFi-critical services. Reboot affected systems after kernel patching to ensure the updated code is loaded.

Detection guidance

Monitoring for exploitation is challenging because the vulnerability manifests as gradual memory exhaustion rather than a detectable attack signature. Implement the following detection strategies: (1) Track kernel memory usage over time on affected WiFi driver systems; sudden growth or inability to reclaim memory under typical load may indicate the leak. (2) Monitor system logs for Out-of-Memory (OOM) events or kernel warnings related to the ath11k driver. (3) Use kernel memory profiling tools (e.g., kmemleak, slabinfo) to identify persistent memory allocations in the ath11k driver module. (4) Correlate memory issues with WiFi configuration changes or error events in driver logs. Note that detection on production systems requires careful tuning to avoid false positives from normal memory usage variance.

Why prioritize this

Prioritize patching based on asset criticality and exposure. High priority: WiFi infrastructure (access points, mesh networks) in shared or multi-tenant environments where local privilege escalation is plausible. Medium priority: Edge devices and embedded systems where kernel updates are infrequent or require scheduled maintenance windows. The MEDIUM CVSS score and local-only attack vector mean this is not an emergency, but timely remediation prevents availability degradation. Systems in environments with strong privilege isolation and limited local user access can defer patching to the next scheduled maintenance window.

Risk score, explained

The CVSS 3.1 score of 5.5 (MEDIUM) reflects: (1) Local attack vector (AV:L)—not remotely exploitable without prior compromise; (2) Low attack complexity (AC:L)—no special conditions needed once local access is obtained; (3) Low privilege requirements (PR:L)—local user privileges suffice; (4) No user interaction required (UI:N); (5) Availability impact only (A:H)—denial of service through resource exhaustion, but no confidentiality or integrity compromise. The score appropriately penalizes remote attack scenarios and privilege escalation attempts, resulting in a medium severity rating suitable for stable but not critical systems.

Frequently asked questions