CVE-2026-43203

High

In the Linux kernel, the following vulnerability has been resolved: atm: fore200e: fix use-after-free in tasklets during device removal When the PCA-200E or SBA-200E adapter is being detached, the fore200e is deallocated. However, the tx_tasklet or rx_tasklet may still be running or pending, leading to use-after-free bug when the already freed fore200e is accessed again in fore200e_tx_tasklet() or fore200e_rx_tasklet(). One of the race conditions can occur as follows: CPU 0 (cleanup) | CPU 1 (tasklet) fore200e_pca_remove_one() | fore200e_interrupt() fore200e_shutdown() | tasklet_schedule() kfree(fore200e) | fore200e_tx_tasklet() | fore200e-> // UAF Fix this by ensuring tx_tasklet or rx_tasklet is properly canceled before the fore200e is released. Add tasklet_kill() in fore200e_shutdown() to synchronize with any pending or running tasklets. Moreover, since fore200e_reset() could prevent further interrupts or data transfers, the tasklet_kill() should be placed after fore200e_reset() to prevent the tasklet from being rescheduled in fore200e_interrupt(). Finally, it only needs to do tasklet_kill() when the fore200e state is greater than or equal to FORE200E_STATE_IRQ, since tasklets are uninitialized in earlier states. In a word, the tasklet_kill() should be placed in the FORE200E_STATE_IRQ branch within the switch...case structure. This bug was identified through static analysis.

Package Linux Kernel
Published 2026-05-06
Last modified 2026-05-11
CVSS version 3.1
Patch available
Yes

CVSS 3.1 score

7.5

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

Weakness type

CWE-416

CVE-2026-43203 is a Use After Free vulnerability

What is Use After Free?

The product references memory after it has been freed, which may cause it to crash, use unexpected values, or execute code. Learn more on MITRE CWE

Affected versions

Linux kernel versions 2.6.12 and later are affected. Fixed in 5.10.252, 5.15.202, 6.1.165, 6.6.128, 6.12.75, 6.18.16, 6.19.6, 7.0 and their respective stable series.

Affected from
≥ 2.6.12
Fixed in
✓ 5.10.252 5.10.x ✓ 5.15.202 5.15.x ✓ 6.1.165 6.1.x ✓ 6.6.128 6.6.x ✓ 6.12.75 6.12.x ✓ 6.18.16 6.18.x ✓ 6.19.6 6.19.x ✓ 7.0

References

The following references provide additional information about CVE-2026-43203 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-2026-43203?

    CVE-2026-43203 is a High severity Linux kernel vulnerability with a CVSS score of 7.5 out of 10 , classified as an Use After Free flaw (CWE-416) . It affects Linux kernel versions from 2.6.12 onward and has been patched in 5.10.252, 5.15.202, 6.1.165 and others. CVE-2026-43203 has not been confirmed as actively exploited and is not listed in the CISA KEV catalog.

  • What is the CVSS score for CVE-2026-43203?

    CVE-2026-43203 has a CVSS score of 7.5 out of 10, rated High severity (CVSS 3.1). The vector string is CVSS:3.1/AV:N/AC:H/PR:N/UI:R/S:U/C:H/I:H/A:H .

  • Is there a patch available for CVE-2026-43203?

    Yes — CVE-2026-43203 has been patched. Fixed versions include 5.10.252, 5.15.202, 6.1.165 and others. 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-2026-43203 actively exploited?

    No — CVE-2026-43203 has not been confirmed as actively exploited. It is not listed in the CISA Known Exploited Vulnerabilities (KEV) catalog.

  • What is Use After Free (CWE-416)?

    The product references memory after it has been freed, which may cause it to crash, use unexpected values, or execute code. View CWE-416 on MITRE CWE →

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