CVE-2024-45010: mptcp: pm: only mark 'subflow' endp as available

Severity: medium (CVSS 5.5 v3.1)
Exploited in the wild: not listed in CISA KEV
EPSS: 0.2% probability of exploitation in the next 30 days
Public exploit or detection template: none known
Published: 2024-09-11 · updated 2026-06-17

Description

In the Linux kernel, the following vulnerability has been resolved: mptcp: pm: only mark 'subflow' endp as available Adding the following warning ... WARN_ON_ONCE(msk->pm.local_addr_used == 0) ... before decrementing the local_addr_used counter helped to find a bug when running the "remove single address" subtest from the mptcp_join.sh selftests. Removing a 'signal' endpoint will trigger the removal of all subflows linked to this endpoint via mptcp_pm_nl_rm_addr_or_subflow() with rm_type == MPTCP_MIB_RMSUBFLOW. This will decrement the local_addr_used counter, which is wrong in this case because this counter is linked to 'subflow' endpoints, and here it is a 'signal' endpoint that is being removed. Now, the counter is decremented, only if the ID is being used outside of mptcp_pm_nl_rm_addr_or_subflow(), only for 'subflow' endpoints, and if the ID is not 0 -- local_addr_used is not taking into account these ones. This marking of the ID as being available, and the decrement is done no matter if a subflow using this ID is currently available, because the subflow could have been closed before.

Affected products

Linux kernel: from 5.13 before 6.1.108; from 6.2 before 6.6.48; from 6.7 before 6.10.7; 6.11-rc1, 6.11-rc2, 6.11-rc3, 6.11-rc4 — fixed in 6.1.108, 6.10.7, 6.6.48

How to fix

Upgrade to a fixed version: Linux kernel 6.1.108, 6.10.7, 6.6.48. Check the vendor advisory for mitigations.

References

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