CVE-2025-68252

Vulnerability

Analysis

CVE-2025-68252 describes a memory leak in the Linux kernel's misc: fastrpc driver. The function fastrpc_map_lookup calls dma_buf_get to obtain a reference to a DMA buffer for comparison purposes, but this reference is never released when the function returns. This results in a dma_buf object leak, as the acquired reference is not freed regardless of whether a matching map is found [1][2].

Exploitation and

Impact

The vulnerability is triggered during normal operation of the fastrpc driver, which is used for remote processor communication (e.g., with DSPs). An attacker with local access and the ability to invoke fastrpc operations could repeatedly trigger the leak, leading to gradual memory exhaustion. The leak does not require special privileges beyond the ability to interact with the fastrpc device, making it a potential vector for denial-of-service attacks.

Mitigation

The fix is straightforward: add a call to dma_buf_put before every return path in fastrpc_map_lookup, ensuring the temporary reference is properly released. The patch has been applied to the Linux kernel stable branches [1][2]. Users should update their kernels to include the fix. No workaround is available other than applying the patch.