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
References
Configurations
Configuration 1 (hide)
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History
No history.
Information
Published : 2026-04-03 16:16
Updated : 2026-07-20 20:10
NVD link : CVE-2026-23472
Mitre link : CVE-2026-23472
CVE.ORG link : CVE-2026-23472
JSON object : View
Products Affected
linux
- linux_kernel
CWE
CWE-835
Loop with Unreachable Exit Condition ('Infinite Loop')