CVE-2025-21689

Medium

In the Linux kernel, the following vulnerability has been resolved: USB: serial: quatech2: fix null-ptr-deref in qt2_process_read_urb() This patch addresses a null-ptr-deref in qt2_process_read_urb() due to an incorrect bounds check in the following: if (newport > serial->num_ports) { dev_err(&port->dev, "%s - port change to invalid port: %i\n", __func__, newport); break; } The condition doesn't account for the valid range of the serial->port buffer, which is from 0 to serial->num_ports - 1. When newport is equal to serial->num_ports, the assignment of "port" in the following code is out-of-bounds and NULL: serial_priv->current_port = newport; port = serial->port[serial_priv->current_port]; The fix checks if newport is greater than or equal to serial->num_ports indicating it is out-of-bounds.

Package Linux Kernel
Published 2025-02-10
Last modified 2025-11-03
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-476

CVE-2025-21689 is a NULL Pointer Dereference vulnerability

What is NULL Pointer Dereference?

The product dereferences a pointer that it expects to be valid but is NULL, typically causing a crash. Learn more on MITRE CWE

Affected versions

Linux kernel versions 3.5 and later are affected. Fixed in 5.4.290, 5.10.234, 5.15.178, 6.1.128, 6.6.75, 6.12.12, 6.13.1, 6.14 and their respective stable series.

Affected from
≥ 3.5
Fixed in
✓ 5.4.290 5.4.x ✓ 5.10.234 5.10.x ✓ 5.15.178 5.15.x ✓ 6.1.128 6.1.x ✓ 6.6.75 6.6.x ✓ 6.12.12 6.12.x ✓ 6.13.1 6.13.x ✓ 6.14

References

The following references provide additional information about CVE-2025-21689 including vendor advisories, patch commits, exploit details, and third-party analysis. Links are sourced from the NIST NVD database.

8 patch commits total View all on NVD

Frequently asked questions

  • What is CVE-2025-21689?

    CVE-2025-21689 is a Medium severity Linux kernel vulnerability with a CVSS score of 5.5 out of 10 , classified as a NULL Pointer Dereference flaw (CWE-476) . It affects Linux kernel versions from 3.5 onward and has been patched in 5.4.290, 5.10.234, 5.15.178 and others. CVE-2025-21689 has not been confirmed as actively exploited and is not listed in the CISA KEV catalog.

  • What is the CVSS score for CVE-2025-21689?

    CVE-2025-21689 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-2025-21689?

    Yes — CVE-2025-21689 has been patched. Fixed versions include 5.4.290, 5.10.234, 5.15.178 and others. If you are running Linux kernel 3.5 or later up to the fix versions, apply the relevant patch for your kernel branch.

  • Is CVE-2025-21689 actively exploited?

    No — CVE-2025-21689 has not been confirmed as actively exploited. It is not listed in the CISA Known Exploited Vulnerabilities (KEV) catalog.

  • What is NULL Pointer Dereference (CWE-476)?

    The product dereferences a pointer that it expects to be valid but is NULL, typically causing a crash. View CWE-476 on MITRE CWE →

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