{"answers":{"affected":"","exploited":"There is no known exploitation of CVE-2025-68227 in the wild and no public exploit code.","fix":"Apply the vendor's patch.","what":"CVE-2025-68227 is a denial of service vulnerability in Linux, published on 16 Dec 2025. Any signed-in user can exploit it over the network, with no action from the victim."},"fix_prompt":"Check this codebase for CVE-2025-68227 and fix it if it is affected.\n\nWhat it is: CVE-2025-68227 is a denial of service vulnerability in Linux, published on 16 Dec 2025. Any signed-in user can exploit it over the network, with no action from the victim.\nExploitation: There is no known exploitation of CVE-2025-68227 in the wild and no public exploit code.\n\nAffected product: Linux. No package-level version data is available, so check the vendor advisory linked from the reference page.\n\nTask:\n1. Search the dependency manifests and lockfiles (for example package.json, package-lock.json, requirements.txt, poetry.lock, uv.lock, pom.xml, build.gradle, go.mod, Cargo.lock, Gemfile.lock) and any Dockerfiles for the affected packages, including transitive dependencies.\n2. If an affected version is in use, upgrade it to the fixed version for its release line with the project's package manager, so the lockfile is regenerated. Prefer the smallest upgrade that fixes it.\n3. If there is no fix, or the upgrade would break the build, do not guess: explain the risk and the safest workaround instead.\n4. Run the tests and summarise what changed and why.\n5. If nothing in the project is affected, say so and change nothing.\n\nReference: https://insights.sbomify.com/CVE-2025-68227/ (Markdown: https://insights.sbomify.com/CVE-2025-68227/index.md)","id":"CVE-2025-68227","markdown":"https://insights.sbomify.com/CVE-2025-68227/index.md","name":"CVE-2025-68227","record":{"aliases":["AZL-72503","BELL-CVE-2025-68227","DEBIAN-CVE-2025-68227","GHSA-fpqf-4vc3-w3r3","ROOT-OS-DEBIAN-12-CVE-2025-68227","ROOT-OS-DEBIAN-13-CVE-2025-68227","ROOT-OS-UBUNTU-2204-CVE-2025-68227","ROOT-OS-UBUNTU-2404-CVE-2025-68227","UBUNTU-CVE-2025-68227"],"analysis":{"component_type":"kernel","fix_type":"patch","impacts":["denial_of_service"],"network_reachable":"yes","non_default_config":true,"product_category":"Linux kernel","requires_auth":"low_privilege","summary":"A local attacker can trigger a kernel warning and potential denial of service in the Linux kernel's MPTCP subsystem when BPF sockmap is used with TCP fallback.","user_interaction":"not_required","vuln_class":"denial_of_service"},"analysis_generated_by":"qwen3.8-flash-next","assigner":"Linux","cpe":[],"cvss":{"score":null,"severity":null,"source":null,"vector":null,"version":null},"cwes":[],"description":"In the Linux kernel, the following vulnerability has been resolved:\n\nmptcp: Fix proto fallback detection with BPF\n\nThe sockmap feature allows bpf syscall from userspace, or based\non bpf sockops, replacing the sk_prot of sockets during protocol stack\nprocessing with sockmap's custom read/write interfaces.\n'''\ntcp_rcv_state_process()\n  syn_recv_sock()/subflow_syn_recv_sock()\n    tcp_init_transfer(BPF_SOCK_OPS_PASSIVE_ESTABLISHED_CB)\n      bpf_skops_established       \u003c== sockops\n        bpf_sock_map_update(sk)   \u003c== call bpf helper\n          tcp_bpf_update_proto()  \u003c== update sk_prot\n'''\n\nWhen the server has MPTCP enabled but the client sends a TCP SYN\nwithout MPTCP, subflow_syn_recv_sock() performs a fallback on the\nsubflow, replacing the subflow sk's sk_prot with the native sk_prot.\n'''\nsubflow_syn_recv_sock()\n  subflow_ulp_fallback()\n    subflow_drop_ctx()\n      mptcp_subflow_ops_undo_override()\n'''\n\nThen, this subflow can be normally used by sockmap, which replaces the\nnative sk_prot with sockmap's custom sk_prot. The issue occurs when the\nuser executes accept::mptcp_stream_accept::mptcp_fallback_tcp_ops().\nHere, it uses sk-\u003esk_prot to compare with the native sk_prot, but this\nis incorrect when sockmap is used, as we may incorrectly set\nsk-\u003esk_socket-\u003eops.\n\nThis fix uses the more generic sk_family for the comparison instead.\n\nAdditionally, this also prevents a WARNING from occurring:\n\nresult from ./scripts/decode_stacktrace.sh:\n------------[ cut here ]------------\nWARNING: CPU: 0 PID: 337 at net/mptcp/protocol.c:68 mptcp_stream_accept \\\n(net/mptcp/protocol.c:4005)\nModules linked in:\n...\n\nPKRU: 55555554\nCall Trace:\n\u003cTASK\u003e\ndo_accept (net/socket.c:1989)\n__sys_accept4 (net/socket.c:2028 net/socket.c:2057)\n__x64_sys_accept (net/socket.c:2067)\nx64_sys_call (arch/x86/entry/syscall_64.c:41)\ndo_syscall_64 (arch/x86/entry/syscall_64.c:63 arch/x86/entry/syscall_64.c:94)\nentry_SYSCALL_64_after_hwframe (arch/x86/entry/entry_64.S:130)\nRIP: 0033:0x7f87ac92b83d\n\n---[ end trace 0000000000000000 ]---","ecosystems":[],"exploits":{"exploitdb":0,"first_seen":null,"github_poc":0,"max_poc_stars":null,"metasploit":0,"nuclei":0,"refs":[],"tier":"none_known"},"has_fix":true,"headline":"mptcp: Fix proto fallback detection with BPF","id":"CVE-2025-68227","indexable":true,"kev":null,"kind":"cve","links":{"ecosystem":null,"product":null,"products":[],"type":"denial_of_service","year":"2025"},"n_packages":0,"n_references":7,"next":{"headline":"drm/plane: Fix create_in_format_blob() return value","id":"CVE-2025-68228"},"packages":[],"prev":{"headline":"smb: client: fix incomplete backport in cfids_invalidation_worker()","id":"CVE-2025-68226"},"products":["Linux"],"published":"2025-12-16","related":[],"sources":[{"class":"attribution","licence":"CVE Terms of Use (MITRE)","name":"CVE List","prefix":"CVE"}],"ssvc":{"automatable":null,"exploitation":null,"technical_impact":null},"state":"PUBLISHED","updated":"2026-05-11","vendors":["Linux"]},"summary":"A local attacker can trigger a kernel warning and potential denial of service in the Linux kernel's MPTCP subsystem when BPF sockmap is used with TCP fallback.","url":"https://insights.sbomify.com/CVE-2025-68227/"}