Linux Kernel Vulnerability in MPTCP Path Manager Affecting Multiple Versions

CVE-2025-21706

Summary

A vulnerability in the Linux kernel related to the MultiPath TCP (MPTCP) implementation allows an incorrect setting of the 'fullmesh' flag on endpoints not intended for this allocation. This can lead to unexpected overrides in the endpoint linking process, which may impact the stability and functionality of ongoing connections. This flaw stems from permissive behavior in the set_flags() function, which potentially exposes 'implicit' endpoints to the 'fullmesh' setting, allowing suboptimal routing of data. Proper validation should be implemented to bolster endpoint management and prevent erroneous configuration.

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