CVE-2026-43190

High

In the Linux kernel, the following vulnerability has been resolved: netfilter: xt_tcpmss: check remaining length before reading optlen Quoting reporter: In net/netfilter/xt_tcpmss.c (lines 53-68), the TCP option parser reads op[i+1] directly without validating the remaining option length. If the last byte of the option field is not EOL/NOP (0/1), the code attempts to index op[i+1]. In the case where i + 1 == optlen, this causes an out-of-bounds read, accessing memory past the optlen boundary (either reading beyond the stack buffer _opt or the following payload).

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

CVSS 3.1 score

8.2

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

Weakness type

CWE-125

CVE-2026-43190 is a Out-of-bounds Read vulnerability

What is Out-of-bounds Read?

The product reads data past the end or before the beginning of the intended buffer. 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-2026-43190 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-2026-43190?

    CVE-2026-43190 is a High severity Linux kernel vulnerability with a CVSS score of 8.2 out of 10 , classified as an Out-of-bounds Read flaw (CWE-125) . 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-2026-43190 has not been confirmed as actively exploited and is not listed in the CISA KEV catalog.

  • What is the CVSS score for CVE-2026-43190?

    CVE-2026-43190 has a CVSS score of 8.2 out of 10, rated High severity (CVSS 3.1). The vector string is CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:N/A:H .

  • Is there a patch available for CVE-2026-43190?

    Yes — CVE-2026-43190 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-2026-43190 actively exploited?

    No — CVE-2026-43190 has not been confirmed as actively exploited. It is not listed in the CISA Known Exploited Vulnerabilities (KEV) catalog.

  • What is Out-of-bounds Read (CWE-125)?

    The product reads data past the end or before the beginning of the intended buffer. View CWE-125 on MITRE CWE →

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