What is CVE-2026-90203?

CVE-2026-90203 is a High severity Linux kernel vulnerability with a CVSS score of 7.1 out of 10, affecting Linux kernel versions from 2.6.29 onward and patched in 5.10.270, 5.15.221, 6.1.188 and others. CVE-2026-90203 has not been confirmed as actively exploited and is not listed in the CISA KEV catalog.

What is the CVSS score for CVE-2026-90203?

CVE-2026-90203 has a CVSS score of 7.1 out of 10, rated High severity. The vector string is CVSS:3.1/AV:L/AC:L/PR:N/UI:R/S:U/C:H/I:N/A:H.

Is there a patch available for CVE-2026-90203?

Yes, CVE-2026-90203 has been patched. Fixed versions include 5.10.270, 5.15.221, 6.1.188 and others. If you are running Linux kernel 2.6.29 or later up to the fix versions, apply the relevant patch for your kernel branch.

Is CVE-2026-90203 actively exploited?

CVE-2026-90203 has not been confirmed as actively exploited and is not listed in the CISA KEV catalog.

CVE-2026-90203

High

In the Linux kernel, the following vulnerability has been resolved: Squashfs: check block offset is not negative If a negative offset is read off disk (for example the offset into the decompressed fragment block), this will cause squashfs_copy_data() to perform an out of bounds access. Fix by checking if offset is negative, and returning 0. This matches existing behaviour where an offset beyond the block returns 0 bytes copied. To trigger this out of bounds access requires a crafted Squashfs filesystem and CAP_SYS_ADMIN to mount it. Unprivileged users will not be able to mount such a filesystem, but once mounted, an unprivileged user can trigger the out of bounds access by reading the crafted file with the negative offset.

Package Linux Kernel

Published 2026-09-17

Last modified 2026-09-18

CVSS version 3.1

Patch available

Yes

CVSS 3.1 score

7.1

out of 10

High

Attack Vector

Local

Attack Complexity

Low

Privileges Required

None

User Interaction

Required

Scope

Unchanged

Confidentiality

High

Integrity

None

Availability

High

Vector string

CVSS:3.1/AV:L/AC:L/PR:N/UI:R/S:U/C:H/I:N/A:H

Affected versions

Linux kernel versions 2.6.29 and later are affected. Fixed in 5.10.270, 5.15.221, 6.1.188, 6.6.157, 6.12.110, 6.18.52, 7.2.6, 7.3-rc1 and their respective stable series.

Affected from

≥ 2.6.29

Fixed in

✓ 5.10.270 5.10.x ✓ 5.15.221 5.15.x ✓ 6.1.188 6.1.x ✓ 6.6.157 6.6.x ✓ 6.12.110 6.12.x ✓ 6.18.52 6.18.x ✓ 7.2.6 7.2.x ✓ 7.3-rc1

References

8 total

Showing 5 of 8 references View all on NVD

Details

CVE ID CVE-2026-90203

Severity High

CVSS score 7.1 / 10

CVSS version 3.1

Published 2026-09-17

Modified 2026-09-18

KEV No

Patch

Yes

Package linux

Frequently asked questions

What is CVE-2026-90203?

CVE-2026-90203 is a High severity Linux kernel vulnerability with a CVSS score of 7.1 out of 10 . It affects Linux kernel versions from 2.6.29 onward and has been patched in 5.10.270, 5.15.221, 6.1.188 and others. CVE-2026-90203 has not been confirmed as actively exploited and is not listed in the CISA KEV catalog.
What is the CVSS score for CVE-2026-90203?

CVE-2026-90203 has a CVSS score of 7.1 out of 10, rated High severity (CVSS 3.1). The vector string is CVSS:3.1/AV:L/AC:L/PR:N/UI:R/S:U/C:H/I:N/A:H.
Is there a patch available for CVE-2026-90203?

Yes. CVE-2026-90203 has been patched. Fixed versions include 5.10.270, 5.15.221, 6.1.188 and others. If you are running Linux kernel 2.6.29 or later up to the fix versions, apply the relevant patch for your kernel branch.
Is CVE-2026-90203 actively exploited?

No. CVE-2026-90203 has not been confirmed as actively exploited. It is not listed in the CISA Known Exploited Vulnerabilities (KEV) catalog.