CVE-2026-97524 - Vulnerability Details

- mptcp: avoid unneeded actions on subflow reset

Description

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

mptcp: avoid unneeded actions on subflow reset

Once in a blue moon, the mptcp receive path can recursively call
mptcp_data_ready() via state change under unlucky error conditions, and
then try to hold the data lock again.

Break the recursion loop explicitly checking for the exceptional
condition.

Add a new flag instead of using an existing one like 'closing', to exit
early in subflow_state_change(), and explicitly flush the RX queue at
reset time.

This avoids unneeded processing to check for available data -- calling
get_mapping_status() and more on a dying subflow -- but also in error
reporting and worker scheduling.

Note that we must consume the currently peeked skb before invoking
mptcp_dss_corruption to avoid consuming it again after the eventual
reset has freed it.

Published: 2026-09-25

Score: 7.5 High

EPSS: < 1% Very Low

KEV: No

Impact:

Action:

Analysis

Impact

The vulnerability is in the Linux kernel’s MPTCP receive path. Under rare error conditions, state changes can cause mptcp_data_ready() to be invoked recursively, leading the code to try to hold the data lock twice and perform additional processing that it normally would skip on a dying subflow.

Affected Systems

All Linux kernel implementations that incorporate MultiPath TCP (MPTCP) and have not yet applied the patches referenced in the advisory are affected. This includes kernels shipped by any distribution that enables MPTCP support until the revision that contains the fix is deployed.

Risk and Exploitability

The CVSS score of 7.5 indicates high severity. The EPSS score is <1%, which points to a very low exploitation probability in the wild. The vulnerability is not listed in the CISA KEV catalog. The advisory notes that the issue is triggered by anomalous subflow reset conditions. Because MPTCP operates over the network, the likely attack vector would be remote network traffic crafted to provoke the state change. This conclusion is inferred from the description; the advisory does not document an existing exploitation technique or proof of concept.

Default status is the baseline for the product, each version can override it (e.g. patched versions marked unaffected).

Vendor Product Default status Versions

Linux

unaffected

Version	Status	Constraints
`fde99e972b8f88cebe619241d7aa43d288ef666a`	affected	< 6d669c740933124eae3df8cfc15995af9bcc6aba
`12c1676d598e3b8dd92a033b623b792cc2ea1ec5`	affected	< 83a7dcdd2b1060484528da70a643125174d47e5a
`35668f8ec84f6c944676e48ecc6bbc5fc8e6fe25`	affected	< a370e56024df0b07e3120c45a9773ae123819fd6
`b8be15d1ae7ea4eedd547c3b3141f592fbddcd30`	affected	< 1962841387087970d75ba8b8d4c2aa2d45705e50
`e32d262c89e2b22cb0640223f953b548617ed8a6`	affected	< 4b7abdcb5ba832fafab679f0d998af39cbc99307
`e32d262c89e2b22cb0640223f953b548617ed8a6`	affected	< b2dbcc1ed48b5ac070a41db4a52aade6823c4df0
`e32d262c89e2b22cb0640223f953b548617ed8a6`	affected	< ce7e4ede01ed3e47a48c0f1ce1d87bf4864bee9f
`e32d262c89e2b22cb0640223f953b548617ed8a6`	affected	< 2b0f561f21b27c40c91ea4975268a06092bd7e9c
`8bfd391bde685df7289b928ce8876a3583be4bfb`	affected	—
`5.10.228`	affected	< 5.10.271
`5.15.169`	affected	< 5.15.222
`6.1.113`	affected	< 6.1.189
`6.6.57`	affected	< 6.6.158
`6.11.4`	affected	< 6.12

Linux

affected

Version	Status	Constraints
`6.12`	affected	—
`0`	unaffected	< 6.12
`5.10.271`	unaffected	≤ 5.10.*
`5.15.222`	unaffected	≤ 5.15.*
`6.1.189`	unaffected	≤ 6.1.*
`6.6.158`	unaffected	≤ 6.6.*
`6.12.111`	unaffected	≤ 6.12.*
`6.18.53`	unaffected	≤ 6.18.*
`7.2.7`	unaffected	≤ 7.2.*
`7.3`	unaffected	≤ *

No data.

Vendor Product Confidence Versions

Linux

Linux Kernel

99%

Version	Status	Scheme	Platform
`[e32d262c89e2b22cb0640223f953b548617ed8a6,4b7abdcb5ba832fafab679f0d998af39cbc99307)`	affected	code_commit	—
`[e32d262c89e2b22cb0640223f953b548617ed8a6,b2dbcc1ed48b5ac070a41db4a52aade6823c4df0)`	affected	code_commit	—
`[e32d262c89e2b22cb0640223f953b548617ed8a6,ce7e4ede01ed3e47a48c0f1ce1d87bf4864bee9)`	affected	code_commit	—
`[e32d262c89e2b22cb0640223f953b548617ed8a6,2b0f561f21b27c40c91ea4975268a06092bd7e9c)`	affected	code_commit	—
`fde99e972b8f88cebe619241d7aa43d288ef666a`	affected	code_commit	—
`12c1676d598e3b8dd92a033b623b792cc2ea1ec5`	affected	code_commit	—
`35668f8ec84f6c944676e48ecc6bbc5fc8e6fe25`	affected	code_commit	—
`b8be15d1ae7ea4eedd547c3b3141f592fbddcd30`	affected	code_commit	—
`8bfd391bde685df7289b928ce8876a3583be4bfb`	affected	code_commit	—
`[5.10.228,5.11)`	affected	semver	—
`[5.15.169,5.16)`	affected	semver	—
`[6.1.113,6.2)`	affected	semver	—
`[6.6.57,6.7)`	affected	semver	—
`[6.11.4,6.12)`	affected	semver	—

Linux

Linux Kernel

99%

Version	Status	Scheme	Platform
`6.12`	affected	semver	—
`[0,6.12)`	unaffected	generic	—
`[6.12.111,6.13.0)`	unaffected	semver	—
`[6.18.53,6.19.0)`	unaffected	semver	—
`[7.2.7,7.3.0)`	unaffected	semver	—
`[7.3-rc4,*]`	unaffected	semver	—

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Remediation

No solution or workaround provided in the CVE record.

OpenCVE Recommended Actions

Apply the latest Linux kernel version that contains the MPTCP patch commits described in the advisory.
If an immediate kernel update is not feasible, disable MPTCP by setting the sysctl parameter net.mptcp.enabled to 0, which turns off the multi‑path functionality.
As a temporary measure, apply the upstream patch manually to the kernel source tree, rebuild, and install the patched kernel.

Generated by OpenCVE AI on October 1, 2026 at 11:49 UTC.

Tracking

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Advisories

Source	ID	Title
Debian DLA	DLA-4817-1	linux-6.12 security update
Debian DLA	DLA-4841-1	linux security update
Debian DSA	DSA-6528-1	linux security update

No CVSS v4.0

Attack Vector Network

Attack Complexity Low

Privileges Required None

Scope Unchanged

Confidentiality Impact None

Integrity Impact None

Availability Impact High

User Interaction None

No CVSS v3.0

No CVSS v2

This CVE is not in the KEV list.

The EPSS score is 0.00725.

Key SSVC decision points have not yet been added.

References

Link	Providers
https://git.kernel.org/pub/scm/linux/security/vulns.git/plain/cve/published/2026/CVE-2026-97524.mbox
https://git.kernel.org/stable/c/1962841387087970d75ba8b8d4c2aa2d45705e50
https://git.kernel.org/stable/c/2b0f561f21b27c40c91ea4975268a06092bd7e9c
https://git.kernel.org/stable/c/4b7abdcb5ba832fafab679f0d998af39cbc99307
https://git.kernel.org/stable/c/6d669c740933124eae3df8cfc15995af9bcc6aba
https://git.kernel.org/stable/c/83a7dcdd2b1060484528da70a643125174d47e5a
https://git.kernel.org/stable/c/a370e56024df0b07e3120c45a9773ae123819fd6
https://git.kernel.org/stable/c/b2dbcc1ed48b5ac070a41db4a52aade6823c4df0
https://git.kernel.org/stable/c/ce7e4ede01ed3e47a48c0f1ce1d87bf4864bee9f
https://nvd.nist.gov/vuln/detail/CVE-2026-97524
https://www.cve.org/CVERecord?id=CVE-2026-97524

History

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

Type	Values Removed	Values Added
References		https://git.kernel.org/stable/c/1962841387087970d75ba8b8d4c2aa2d45705e50 https://git.kernel.org/stable/c/6d669c740933124eae3df8cfc15995af9bcc6aba https://git.kernel.org/stable/c/83a7dcdd2b1060484528da70a643125174d47e5a https://git.kernel.org/stable/c/a370e56024df0b07e3120c45a9773ae123819fd6

Thu, 01 Oct 2026 10:30:00 +0000

Type	Values Removed	Values Added
Weaknesses	CWE-674

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

Type	Values Removed	Values Added
Weaknesses		CWE-764
References		https://git.kernel.org/pub/scm/linux/security/vulns.git/plain/cve/published/2026/CVE-2026-97524.mbox https://nvd.nist.gov/vuln/detail/CVE-2026-97524 https://www.cve.org/CVERecord?id=CVE-2026-97524
Metrics	threat_severity `None`	threat_severity `Moderate`

Sat, 26 Sep 2026 00:45:00 +0000

Type	Values Removed	Values Added
Weaknesses		CWE-674

Fri, 25 Sep 2026 15:00:00 +0000

Type	Values Removed	Values Added
Metrics		cvssV3_1 `{'score': 7.5, 'vector': 'CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H'}`

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: avoid unneeded actions on subflow reset Once in a blue moon, the mptcp receive path can recursively call mptcp_data_ready() via state change under unlucky error conditions, and then try to hold the data lock again. Break the recursion loop explicitly checking for the exceptional condition. Add a new flag instead of using an existing one like 'closing', to exit early in subflow_state_change(), and explicitly flush the RX queue at reset time. This avoids unneeded processing to check for available data -- calling get_mapping_status() and more on a dying subflow -- but also in error reporting and worker scheduling. Note that we must consume the currently peeked skb before invoking mptcp_dss_corruption to avoid consuming it again after the eventual reset has freed it.
Title		mptcp: avoid unneeded actions on subflow reset
First Time appeared		Linux Linux linux Kernel
CPEs		cpe:2.3:o:linux:linux_kernel::::::::
Vendors & Products		Linux Linux linux Kernel
References		https://git.kernel.org/stable/c/2b0f561f21b27c40c91ea4975268a06092bd7e9c https://git.kernel.org/stable/c/4b7abdcb5ba832fafab679f0d998af39cbc99307 https://git.kernel.org/stable/c/b2dbcc1ed48b5ac070a41db4a52aade6823c4df0 https://git.kernel.org/stable/c/ce7e4ede01ed3e47a48c0f1ce1d87bf4864bee9f

Subscriptions

Linux Linux Kernel

MITRE

Status: PUBLISHED

Assigner: Linux

Published: 2026-09-25T10:21:27.668Z

Updated: 2026-10-19T09:08:42.302Z

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

Link: CVE-2026-97524

Vulnrichment

No data.

NVD

Status : Received

Published: 2026-09-25T11:17:02.520

Modified: 2026-10-19T10:17:21.260

Link: CVE-2026-97524

Redhat

Severity : Moderate

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

Links: CVE-2026-97524 - Bugzilla

OpenCVE Enrichment

Updated: 2026-10-01T12:00:06Z

Weaknesses

CWE-764
Multiple Locks of a Critical Resource

Impact

Affected Systems

Risk and Exploitability

Tracking

Attack Vector Network

Attack Complexity Low

Privileges Required None

Scope Unchanged

Confidentiality Impact None

Integrity Impact None

Availability Impact High

User Interaction None

Subscriptions

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