Description
In the Linux kernel, the following vulnerability has been resolved:

mptcp: fix bad accounting in __mptcp_subflow_push_pending()

If __subflow_push_pending() errors out we should avoid updating the
copied byte counters, to avoid mismatch push call later on.
Published: 2026-09-25
Score: 5.5 Medium
EPSS: < 1% Very Low
KEV: No
Impact: Integrity
Action: Install updated kernel
AI Analysis

Impact

The Linux kernel bug involves incorrect accounting in the MPTCP subflow push path. When the __mptcp_subflow_push_pending() function fails, the code mistakenly updates byte counters, resulting in mismatched accounting values that can corrupt traffic metrics and potentially lead to unreliable data transmission. This flaw falls under improper handling of counters and is related to CWE-252. The likely attack vector is local to the kernel, as inferred from the description.

Affected Systems

Linux kernel versions prior to the patch containing the commit identified in multiple kernel stable branches are affected. The vulnerability is present in all mainstream distributions that ship the unpatched kernel, regardless of vendor, as the issue is in the Linux kernel source itself. Based on the commit references, the affected kernels are inferred to be all releases before the patch.

Risk and Exploitability

Because the defect occurs during subflow management, it is only exploitable within a system running the affected kernel; remote exploitation is unlikely. The CVSS score is 5.5 and the EPSS score is < 1%, indicating a low probability of exploitation. The flaw does not grant arbitrary code execution but can degrade data integrity and potentially disrupt MPTCP connections. As the bug is purely internal bookkeeping, the risk is primarily integrity and availability of MPTCP traffic. The vulnerability is not listed in CISA’s KEV catalog. The likely attack vector is local to the kernel and requires kernel-level privileges, based on the description.

Generated by OpenCVE AI on October 1, 2026 at 13:49 UTC.

Remediation

No solution or workaround provided in the CVE record.

OpenCVE Recommended Actions

  • Apply the kernel patch that fixes accounting in __mptcp_subflow_push_pending() by updating to a kernel release that incorporates the commit.
  • If patching is not immediately possible, disable MPTCP or restrict its usage until the kernel can be updated.
  • Run diagnostic tests that trigger subflow push failures to ensure that counters are not updated, verifying the fix’s effectiveness.

Generated by OpenCVE AI on October 1, 2026 at 13:49 UTC.

Tracking

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Advisories
Source ID Title
Debian DLA Debian DLA DLA-4817-1 linux-6.12 security update
Debian DSA Debian DSA DSA-6528-1 linux security update
History

Sat, 03 Oct 2026 11:15:00 +0000


Thu, 01 Oct 2026 11:45:00 +0000

Type Values Removed Values Added
Weaknesses CWE-665

Tue, 29 Sep 2026 13:15:00 +0000

Type Values Removed Values Added
Weaknesses CWE-252
References
Metrics threat_severity

None

cvssV3_1

{'score': 5.5, 'vector': 'CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H'}

threat_severity

Low


Sat, 26 Sep 2026 00:00:00 +0000

Type Values Removed Values Added
Weaknesses CWE-665

Fri, 25 Sep 2026 10:30:00 +0000

Type Values Removed Values Added
Description In the Linux kernel, the following vulnerability has been resolved: mptcp: fix bad accounting in __mptcp_subflow_push_pending() If __subflow_push_pending() errors out we should avoid updating the copied byte counters, to avoid mismatch push call later on.
Title mptcp: fix bad accounting in __mptcp_subflow_push_pending()
First Time appeared Linux
Linux linux Kernel
CPEs cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*
Vendors & Products Linux
Linux linux Kernel
References

Subscriptions

Linux Linux Kernel
cve-icon MITRE

Status: PUBLISHED

Assigner: Linux

Published:

Updated: 2026-10-19T09:08:40.383Z

Reserved: 2026-09-24T16:01:01.152Z

Link: CVE-2026-97522

cve-icon Vulnrichment

No data.

cve-icon NVD

Status : Received

Published: 2026-09-25T11:17:02.297

Modified: 2026-10-19T10:17:21.023

Link: CVE-2026-97522

cve-icon Redhat

Severity : Low

Publid Date: 2026-09-25T00:00:00Z

Links: CVE-2026-97522 - Bugzilla

cve-icon OpenCVE Enrichment

Updated: 2026-10-01T14:00:10Z

Weaknesses