CVE-2022-50663

A memory leak vulnerability exists in the Linux kernel's stmmac (STMicroelectronics MAC) driver. In the stmmac_dvr_probe() function, a bitmap (priv->af_xdp_zc_qps) is allocated but not freed if create_singlethread_workqueue() fails. This missing bitmap_free() call leads to a memory leak over time [1].

The vulnerability is triggered during driver probe when the workqueue creation fails due to resource constraints or other errors. While the specific conditions are rare, the issue can be exploited by an attacker with local access who can trigger the probe failure, potentially repeatedly.

Impact is limited to memory exhaustion, which could degrade system performance or lead to a denial-of-service condition. No privilege escalation or code execution is implied.

Both the mainline and stable kernels have been patched to address this issue, as seen in the referenced commits [1][2]. Users are advised to update their kernels to versions containing the fix.