CVE-2025-71126

kernel: Linux kernel: Deadlock due to MPTCP packet reinjection during fallback

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Severity

Moderate

Red Hat Product Security

4.4

CVSS 3.1

Review impact separately from score.

Published · January 14, 2026

Updated · October 29, 2026

Description

A flaw was found in the Linux kernel's Multipath TCP (MPTCP) implementation. A remote attacker could exploit this vulnerability when the packet scheduler attempts to reinject packets after receiving an MP_FAIL message but before the infinite map has been fully transmitted. This timing issue can lead to a deadlock, causing a denial of service.

Statement

MPTCP is disabled by default in RHEL, and enabling it requires superuser permissions.

CVSS score applicability

The CVSS score(s) listed for this vulnerability do not reflect the associated product's status, and are included for informational purposes to better understand the severity of this vulnerability.

Mitigation

No mitigation is specified in collected source.

CVSS / CWE

CVSS 3.1 · 4.4
CVSS:3.1/AV:L/AC:L/PR:H/UI:N/S:U/C:N/I:N/A:H

CWE-833 · Deadlock