What is CVE-2026-43209?

CVE-2026-43209 is a Medium severity Linux kernel vulnerability with a CVSS score of 5.5 out of 10, affecting Linux kernel versions from 2.6.12 onward and patched in 5.10.252, 5.15.202, 6.1.165 and others. CVE-2026-43209 has not been confirmed as actively exploited and is not listed in the CISA KEV catalog.

What is the CVSS score for CVE-2026-43209?

CVE-2026-43209 has a CVSS score of 5.5 out of 10, rated Medium severity. 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-2026-43209?

Yes, CVE-2026-43209 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-2026-43209 actively exploited?

CVE-2026-43209 has not been confirmed as actively exploited and is not listed in the CISA KEV catalog.

CVE-2026-43209

Medium

In the Linux kernel, the following vulnerability has been resolved: minix: Add required sanity checking to minix_check_superblock() The fs/minix implementation of the minix filesystem does not currently support any other value for s_log_zone_size than 0. This is also the only value supported in util-linux; see mkfs.minix.c line 511. In addition, this patch adds some sanity checking for the other minix superblock fields, and moves the minix_blocks_needed() checks for the zmap and imap also to minix_check_super_block(). This also closes a related syzbot bug report.

Package Linux Kernel

Published 2026-05-06

Last modified 2026-05-11

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

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-2026-43209 including vendor advisories, patch commits, exploit details, and third-party analysis. Links are sourced from the NIST NVD database.

Kernel patch commit
https://git.kernel.org/stable/c/1efc128ee4adbc23e082715425ff895449d233bc
Patch
Kernel patch commit
https://git.kernel.org/stable/c/2bb588cede1c1969e49c0a2822c8cb8b346b7682
Patch
Kernel patch commit
https://git.kernel.org/stable/c/31fefc18096cdc5549cfa54964d90e0b3229aedc
Patch

8 patch commits total View all on NVD

Details

CVE ID CVE-2026-43209

Severity Medium

CVSS score 5.5 / 10

CVSS version 3.1

Published 2026-05-06

Modified 2026-05-11

KEV No

Patch

Yes

Package linux

Frequently asked questions

What is CVE-2026-43209?

CVE-2026-43209 is a Medium severity Linux kernel vulnerability with a CVSS score of 5.5 out of 10 . 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-2026-43209 has not been confirmed as actively exploited and is not listed in the CISA KEV catalog.
What is the CVSS score for CVE-2026-43209?

CVE-2026-43209 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-2026-43209?

Yes — CVE-2026-43209 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-2026-43209 actively exploited?

No — CVE-2026-43209 has not been confirmed as actively exploited. It is not listed in the CISA Known Exploited Vulnerabilities (KEV) catalog.