CVE-2024-35894: In the Linux kernel, the following vulnerability has been resolved: mptcp: prevent BPF accessing lowat from a subflow socket.

In the Linux kernel, the following vulnerability has been resolved: mptcp: prevent BPF accessing lowat from a subflow socket.

In the Linux kernel, the following vulnerability has been resolved: mptcp: prevent BPF accessing lowat from a subflow socket. Alexei reported the following splat: WARNING: CPU: 32 PID: 3276 at net/mptcp/subflow.c:1430 subflow_data_ready+0x147/0x1c0 Modules linked in: dummy bpf_testmod(O) [last unloaded: bpf_test_no_cfi(O)] CPU: 32 PID: 3276 Comm: test_progs Tainted: GO 6.8.0-12873-g2c43c33bfd23 Call Trace: <TASK> mptcp_set_rcvlowat+0x79/0x1d0 sk_setsockopt+0x6c0/0x1540 __bpf_setsockopt+0x6f/0x90 bpf_sock_ops_setsockopt+0x3c/0x90 bpf_prog_509ce5db2c7f9981_bpf_test_sockopt_int+0xb4/0x11b bpf_prog_dce07e362d941d2b_bpf_test_socket_sockopt+0x12b/0x132 bpf_prog_348c9b5faaf10092_skops_sockopt+0x954/0xe86 __cgroup_bpf_run_filter_sock_ops+0xbc/0x250 tcp_connect+0x879/0x1160 tcp_v6_connect+0x50c/0x870 mptcp_connect+0x129/0x280 __inet_stream_connect+0xce/0x370 inet_stream_connect+0x36/0x50 bpf_trampoline_6442491565+0x49/0xef inet_stream_connect+0x5/0x50 __sys_connect+0x63/0x90 __x64_sys_connect+0x14/0x20 The root cause of the issue is that bpf allows accessing mptcp-level proto_ops from a tcp subflow scope. Fix the issue detecting the problem

Description from the National Vulnerability Database, published by 416baaa9-dc9f-4396-8d5f-8c081fb06d67

What it means for a small business

Linux is on the computers, phones or browsers your team uses every day. Turn on automatic updates and restart: most of these fixes only take effect after a restart.

How likely is an attack? The Exploit Prediction Scoring System, run by FIRST (the global association of security response teams), puts the odds of this one being exploited in the next 30 days at 0.22%, higher than 12% of CVEs. That’s low, but low isn’t zero, and the odds jump the day someone publishes an exploit. Scored October 29, 2026, updated daily.

Check your own setup

Website check: reads what your site runs from the outside (WordPress version, plugins it can see, old server software) and matches it against this database.
Server check: what your web server says about itself, and whether that version has known flaws.

Sources

Part of the Huttenlocher Technologies vulnerability database, refreshed twice a day from CISA and the NVD. The title, category and plain-language guidance are ours; check the linked record before acting on a detail. This is general guidance, not a review of your systems.

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