CVE-2026-23472 in Kernel
Résumé (Anglaise)
In the Linux kernel, the following vulnerability has been resolved:
serial: core: fix infinite loop in handle_tx() for PORT_UNKNOWN
uart_write_room() and uart_write() behave inconsistently when
xmit_buf is NULL (which happens for PORT_UNKNOWN ports that were
never properly initialized):
- uart_write_room() returns kfifo_avail() which can be > 0
- uart_write() checks xmit_buf and returns 0 if NULL
This inconsistency causes an infinite loop in drivers that rely on
tty_write_room() to determine if they can write:
while (tty_write_room(tty) > 0) {
written = tty->ops->write(...);
// written is always 0, loop never exits
}
For example, caif_serial's handle_tx() enters an infinite loop when
used with PORT_UNKNOWN serial ports, causing system hangs.
Fix by making uart_write_room() also check xmit_buf and return 0 if
it's NULL, consistent with uart_write().
Reproducer: https://gist.github.com/mrpre/d9a694cc0e19828ee3bc3b37983fde13
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Responsable
Linux
Réserver
13/01/2026
Divulgation
03/04/2026
Statut
Confirmé
Entrées
VulDB provides additional information and datapoints for this CVE:
| ID | Vulnérabilité | CWE | Exp | Con | CVE |
|---|---|---|---|---|---|
| 355140 | Linux Kernel serial handle_tx déni de service | 835 | Non défini | Correctif officiel | CVE-2026-23472 |