CVE-2026-23472

Medium

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

Package Linux Kernel
Published 2026-04-03
Last modified 2026-05-26
CVSS version 3.1
Patch available
Yes

CVSS 3.1 score

5.5

out of 10
Medium
Attack Vector
Local
Attack Complexity
Low
Privileges Required
Low
User Interaction
None
Scope
Unchanged
Confidentiality
Low
Integrity
None
Availability
High
Vector string
CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H

Weakness type

CWE-835

CVE-2026-23472 is a Infinite Loop vulnerability

What is Infinite Loop?

The product contains an iteration that does not exit even when it should. Learn more on MITRE CWE

Affected versions

Linux kernel versions 2.6.12 and later are affected. Fixed in 6.18.20, 6.19.10, 7.0 and their respective stable series.

Affected from
≥ 2.6.12
Fixed in
✓ 6.18.20 6.18.x ✓ 6.19.10 6.19.x ✓ 7.0

References

The following references provide additional information about CVE-2026-23472 including vendor advisories, patch commits, exploit details, and third-party analysis. Links are sourced from the NIST NVD database.

Frequently asked questions

  • What is CVE-2026-23472?

    CVE-2026-23472 is a Medium severity Linux kernel vulnerability with a CVSS score of 5.5 out of 10 , classified as an Infinite Loop flaw (CWE-835) . It affects Linux kernel versions from 2.6.12 onward and has been patched in 6.18.20, 6.19.10 and 7.0. CVE-2026-23472 has not been confirmed as actively exploited and is not listed in the CISA KEV catalog.

  • What is the CVSS score for CVE-2026-23472?

    CVE-2026-23472 has a CVSS score of 5.5 out of 10, rated Medium severity (CVSS 3.1). The vector string is CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H .

  • Is there a patch available for CVE-2026-23472?

    Yes — CVE-2026-23472 has been patched. Fixed versions include 6.18.20, 6.19.10 and 7.0. If you are running Linux kernel 2.6.12 or later up to the fix versions, apply the relevant patch for your kernel branch.

  • Is CVE-2026-23472 actively exploited?

    No — CVE-2026-23472 has not been confirmed as actively exploited. It is not listed in the CISA Known Exploited Vulnerabilities (KEV) catalog.

  • What is Infinite Loop (CWE-835)?

    The product contains an iteration that does not exit even when it should. View CWE-835 on MITRE CWE →

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