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).

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History

Thu, 07 May 2026 04:00:00 +0000

Type Values Removed Values Added
Weaknesses CWE-125

Thu, 07 May 2026 00:15:00 +0000

Type Values Removed Values Added
Weaknesses CWE-130
References
Metrics threat_severity

None

cvssV3_1

{'score': 7.0, 'vector': 'CVSS:3.1/AV:L/AC:H/PR:L/UI:N/S:U/C:H/I:H/A:H'}

threat_severity

Important


Wed, 06 May 2026 14:30:00 +0000

Type Values Removed Values Added
Weaknesses CWE-125

Wed, 06 May 2026 12:15:00 +0000

Type Values Removed Values Added
Description 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).
Title netfilter: xt_tcpmss: check remaining length before reading optlen
First Time appeared Linux
Linux linux Kernel
CPEs cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*
Vendors & Products Linux
Linux linux Kernel
References

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cve-icon MITRE

Status: PUBLISHED

Assigner: Linux

Published:

Updated: 2026-05-06T11:27:59.798Z

Reserved: 2026-05-01T14:12:55.992Z

Link: CVE-2026-43190

cve-icon Vulnrichment

No data.

cve-icon NVD

Status : Awaiting Analysis

Published: 2026-05-06T12:16:37.843

Modified: 2026-05-06T13:07:51.607

Link: CVE-2026-43190

cve-icon Redhat

Severity : Important

Publid Date: 2026-05-06T00:00:00Z

Links: CVE-2026-43190 - Bugzilla

cve-icon OpenCVE Enrichment

Updated: 2026-05-07T06:15:23Z

Weaknesses