CVE-2026-53158: Linux Kernel

Medium severity, CVSS 5.5. EPSS: 0.1% chance of exploitation in the next 30 days.

In the Linux kernel, the following vulnerability has been resolved: misc: fastrpc: Fix NULL pointer dereference in rpmsg callback A NULL pointer dereference was observed on Hawi at boot when the DSP sends a glink message before fastrpc_rpmsg_probe() has completed initialization: Unable to handle kernel NULL pointer dereference at virtual address 0000000000000178 pc : _raw_spin_lock_irqsave+0x34/0x8c lr : fastrpc_rpmsg_callback+0x3c/0xcc [fastrpc] ... Call trace: _raw_spin_lock_irqsave+0x34/0x8c (P) fastrpc_rpmsg_callback+0x3c/0xcc [fastrpc] qcom_glink_native_rx+0x538/0x6a4 qcom_glink_smem_intr+0x14/0x24 [qcom_glink_smem] The faulting address 0x178 corresponds to the lock variable inside struct fastrpc_channel_ctx, confirming that cctx is NULL when fastrpc_rpmsg_callback() attempts to take the spinlock. There are two issues here. First, dev_set_drvdata() is called before spin_lock_init() and idr_init(), leaving a window where the callback can retrieve a valid cctx pointer but operate on an uninitialized spinlock. Second, the rpmsg channel becomes live as soon as the driver is bound, so fastrpc_rpmsg_callback() can fire before dev_set_drvdata() is called at all, resulting in dev_get_drvdata() returning NULL. Fix both issues by moving all cctx initialization ahead of dev_set_drvdata() so the structure is fully initialized before it becomes visible to the callback, and add a NULL check in fastrpc_rpmsg_callback() as a guard against any remaining window.

Affected products

• Linux Linux Kernel: from 5.1, before 5.10.260 (fixed in 5.10.260); from 5.11, before 5.15.211 (fixed in 5.15.211); from 5.16, before 6.1.177 (fixed in 6.1.177); from 6.2, before 6.6.143 (fixed in 6.6.143); from 6.7, before 6.12.94 (fixed in 6.12.94); from 6.13, before 6.18.36 (fixed in 6.18.36); …

Published 2026-06-25. Last modified 2026-07-07.