CVE-2026-23281wifi: libertas: fix use-after-free in lbs_free_adapter()

Official description

In the Linux kernel, the following vulnerability has been resolved: wifi: libertas: fix use-after-free in lbs_free_adapter() The lbs_free_adapter() function uses timer_delete() (non-synchronous) for both command_timer and tx_lockup_timer before the structure is freed. This is incorrect because timer_delete() does not wait for any running timer callback to complete. If a timer callback is executing when lbs_free_adapter() is called, the callback will access freed memory since lbs_cfg_free() frees the containing structure immediately after lbs_free_adapter() returns. Both timer callbacks (lbs_cmd_timeout_handler and lbs_tx_lockup_handler) access priv->driver_lock, priv->cur_cmd, priv->dev, and other fields, which would all be use-after-free violations. Use timer_delete_sync() instead to ensure any running timer callback has completed before returning. This bug was introduced in commit 8f641d93c38a ("libertas: detect TX lockups and reset hardware") where del_timer() was used instead of del_timer_sync() in the cleanup path. The command_timer has had the same issue since the driver was first written.

Affected packages & fixed versions

Affected products (as reported)

References

• https://git.kernel.org/stable/c/b15e0fa7adb4de3a03aee9e6fc4d83e5cf0a65e4
• https://git.kernel.org/stable/c/09f3c30ab3b1371eaf9676a1b8add57bca763083
• https://git.kernel.org/stable/c/3f9dec4a6d95d7f1f5e9e9dfdfa173c053bba8dc
• https://git.kernel.org/stable/c/3c5c818c78b03a1725f3dcd566865c77b48dd3a6
• https://git.kernel.org/stable/c/d0155fe68f31b339961cf2d4f92937d57e9384e6
• https://git.kernel.org/stable/c/ed7d30f90b77f73a47498686ede83f622b7e4f0d
• https://git.kernel.org/stable/c/a9f55b14486426d907459bced5825a25063bd922
• https://git.kernel.org/stable/c/03cc8f90d0537fcd4985c3319b4fafbf2e3fb1f0
• https://cert-portal.siemens.com/productcert/html/ssa-784472.html