CVE-2021-47152: mptcp: fix data stream corruption

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: 2024-03-25 · updated 2026-08-04
Weakness: CWE-787

Description

In the Linux kernel, the following vulnerability has been resolved: mptcp: fix data stream corruption Maxim reported several issues when forcing a TCP transparent proxy to use the MPTCP protocol for the inbound connections. He also provided a clean reproducer. The problem boils down to 'mptcp_frag_can_collapse_to()' assuming that only MPTCP will use the given page_frag. If others - e.g. the plain TCP protocol - allocate page fragments, we can end-up re-using already allocated memory for mptcp_data_frag. Fix the issue ensuring that the to-be-expanded data fragment is located at the current page frag end. v1 -> v2: - added missing fixes tag (Mat)

Affected products

Linux kernel: from 5.7 before 5.10.42; from 5.11 before 5.12.9; 5.13-rc1, 5.13-rc2, 5.13-rc3 — fixed in 5.10.42, 5.12.9

How to fix

Upgrade to a fixed version: Linux kernel 5.10.42, 5.12.9. Check the vendor advisory for mitigations.

References

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