CVE-2026-98748serial: 8250_bcm7271: fix use-after-free in brcmuart_remove()

Official description

In the Linux kernel, the following vulnerability has been resolved: serial: 8250_bcm7271: fix use-after-free in brcmuart_remove() brcmuart_handle_irq() starts priv->hrt to work around a receive-timeout quirk of the 8250 core when hardware flow control is enabled; the timer callback brcmuart_hrtimer_func() dereferences priv. brcmuart_remove() cancels the hrtimer before it unregisters the port, so a receive-timeout interrupt that arrives in between re-arms the timer. After devm frees priv, the callback runs on freed memory. Unregister the port before cancelling the hrtimer. serial8250_unregister_port() shuts the port down and frees its IRQ, so brcmuart_handle_irq() can no longer restart the timer, and the final hrtimer_cancel() drains any timer that was armed before or during the unregister. This issue was found by an in-house static analysis tool.

Affected packages & fixed versions

Affected products (as reported)

References

• https://git.kernel.org/stable/c/134d239558f2ac2602fad2392ec3e6d8d76af7d8
• https://git.kernel.org/stable/c/dad9fb86829ee96bbc6315d7209ceb24820ef889
• https://git.kernel.org/stable/c/dd81650bec58ac70e5dfde2ec390acc1f0d1ed76
• https://git.kernel.org/stable/c/f5ce06e648d775cc1ccf66f4f594bb8b559a7d8e
• https://git.kernel.org/stable/c/e32440fa536af96bdbc61d933a7c3a920b965edc
• https://git.kernel.org/stable/c/0794ba5332754866b2f1c0cca668775be3ffcf0a
• https://git.kernel.org/stable/c/189b9dc8c96ec9486482f27c1372b04a7152175e