{"answers":{"affected":"It affects 1 product.","exploited":"There is no known exploitation of CVE-2025-71126 in the wild and no public exploit code.","fix":"Apply the vendor's patch.","what":"CVE-2025-71126 is a high-severity vulnerability in Linux kernel, published on 14 Jan 2026. An attacker can exploit it over the internet without logging in, with no action from the victim."},"fix_prompt":"Check this codebase for CVE-2025-71126 and fix it if it is affected.\n\nWhat it is: CVE-2025-71126 is a high-severity vulnerability in Linux kernel, published on 14 Jan 2026. An attacker can exploit it over the internet without logging in, with no action from the victim.\nExploitation: There is no known exploitation of CVE-2025-71126 in the wild and no public exploit code.\n\nAffected product: Linux kernel. 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-2025-71126/ (Markdown: https://insights.sbomify.com/CVE-2025-71126/index.md)","id":"CVE-2025-71126","markdown":"https://insights.sbomify.com/CVE-2025-71126/index.md","name":"CVE-2025-71126","record":{"aliases":["BELL-CVE-2025-71126","DEBIAN-CVE-2025-71126","GHSA-cqcj-p3px-rprf","ROOT-OS-DEBIAN-12-CVE-2025-71126","ROOT-OS-DEBIAN-13-CVE-2025-71126","ROOT-OS-UBUNTU-2404-CVE-2025-71126","UBUNTU-CVE-2025-71126"],"analysis":{"component_type":"kernel","fix_type":"patch","impacts":["denial_of_service"],"network_reachable":"yes","non_default_config":false,"product_category":"Linux kernel","requires_auth":"none","summary":"A deadlock in the Linux kernel MPTCP subsystem allows local attackers to cause a denial of service via recursive locking during fallback operations.","user_interaction":"not_required","vuln_class":"race_condition"},"analysis_generated_by":"qwen3.8-flash-next","assigner":"Linux","cpe":[{"product":"linux_kernel","vendor":"linux"}],"cvss":{"score":7.5,"severity":"high","source":"cna","vector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H","version":"3.1"},"cwes":[{"id":"CWE-667","name":"Improper Locking"},{"id":"CWE-362","name":"Concurrent Execution using Shared Resource with Improper Synchronization"}],"description":"In the Linux kernel, the following vulnerability has been resolved:\n\nmptcp: avoid deadlock on fallback while reinjecting\n\nJakub reported an MPTCP deadlock at fallback time:\n\n WARNING: possible recursive locking detected\n 6.18.0-rc7-virtme #1 Not tainted\n --------------------------------------------\n mptcp_connect/20858 is trying to acquire lock:\n ff1100001da18b60 (\u0026msk-\u003efallback_lock){+.-.}-{3:3}, at: __mptcp_try_fallback+0xd8/0x280\n\n but task is already holding lock:\n ff1100001da18b60 (\u0026msk-\u003efallback_lock){+.-.}-{3:3}, at: __mptcp_retrans+0x352/0xaa0\n\n other info that might help us debug this:\n  Possible unsafe locking scenario:\n\n        CPU0\n        ----\n   lock(\u0026msk-\u003efallback_lock);\n   lock(\u0026msk-\u003efallback_lock);\n\n  *** DEADLOCK ***\n\n  May be due to missing lock nesting notation\n\n 3 locks held by mptcp_connect/20858:\n  #0: ff1100001da18290 (sk_lock-AF_INET){+.+.}-{0:0}, at: mptcp_sendmsg+0x114/0x1bc0\n  #1: ff1100001db40fd0 (k-sk_lock-AF_INET#2){+.+.}-{0:0}, at: __mptcp_retrans+0x2cb/0xaa0\n  #2: ff1100001da18b60 (\u0026msk-\u003efallback_lock){+.-.}-{3:3}, at: __mptcp_retrans+0x352/0xaa0\n\n stack backtrace:\n CPU: 0 UID: 0 PID: 20858 Comm: mptcp_connect Not tainted 6.18.0-rc7-virtme #1 PREEMPT(full)\n Hardware name: Bochs, BIOS Bochs 01/01/2011\n Call Trace:\n  \u003cTASK\u003e\n  dump_stack_lvl+0x6f/0xa0\n  print_deadlock_bug.cold+0xc0/0xcd\n  validate_chain+0x2ff/0x5f0\n  __lock_acquire+0x34c/0x740\n  lock_acquire.part.0+0xbc/0x260\n  _raw_spin_lock_bh+0x38/0x50\n  __mptcp_try_fallback+0xd8/0x280\n  mptcp_sendmsg_frag+0x16c2/0x3050\n  __mptcp_retrans+0x421/0xaa0\n  mptcp_release_cb+0x5aa/0xa70\n  release_sock+0xab/0x1d0\n  mptcp_sendmsg+0xd5b/0x1bc0\n  sock_write_iter+0x281/0x4d0\n  new_sync_write+0x3c5/0x6f0\n  vfs_write+0x65e/0xbb0\n  ksys_write+0x17e/0x200\n  do_syscall_64+0xbb/0xfd0\n  entry_SYSCALL_64_after_hwframe+0x4b/0x53\n RIP: 0033:0x7fa5627cbc5e\n Code: 4d 89 d8 e8 14 bd 00 00 4c 8b 5d f8 41 8b 93 08 03 00 00 59 5e 48 83 f8 fc 74 11 c9 c3 0f 1f 80 00 00 00 00 48 8b 45 10 0f 05 \u003cc9\u003e c3 83 e2 39 83 fa 08 75 e7 e8 13 ff ff ff 0f 1f 00 f3 0f 1e fa\n RSP: 002b:00007fff1fe14700 EFLAGS: 00000202 ORIG_RAX: 0000000000000001\n RAX: ffffffffffffffda RBX: 0000000000000005 RCX: 00007fa5627cbc5e\n RDX: 0000000000001f9c RSI: 00007fff1fe16984 RDI: 0000000000000005\n RBP: 00007fff1fe14710 R08: 0000000000000000 R09: 0000000000000000\n R10: 0000000000000000 R11: 0000000000000202 R12: 00007fff1fe16920\n R13: 0000000000002000 R14: 0000000000001f9c R15: 0000000000001f9c\n\nThe packet scheduler could attempt a reinjection after receiving an\nMP_FAIL and before the infinite map has been transmitted, causing a\ndeadlock since MPTCP needs to do the reinjection atomically from WRT\nfallback.\n\nAddress the issue explicitly avoiding the reinjection in the critical\nscenario. Note that this is the only fallback critical section that\ncould potentially send packets and hit the double-lock.","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: avoid deadlock on fallback while reinjecting","id":"CVE-2025-71126","indexable":true,"kev":null,"kind":"cve","links":{"ecosystem":null,"product":"linux:linux_kernel","products":["linux:linux_kernel"],"type":"race_condition","year":"2025"},"n_packages":0,"n_references":5,"next":{"headline":"wifi: mac80211: Discard Beacon frames to non-broadcast address","id":"CVE-2025-71127"},"packages":[],"prev":{"headline":"tracing: Do not register unsupported perf events","id":"CVE-2025-71125"},"products":["Linux"],"published":"2026-01-14","related":[{"cvss_score":8.8,"headline":"Linux Kernel Out-of-Bounds Write","id":"CVE-2026-53266","kev_date_added":"2026-09-18","published":"2026-06-25"},{"cvss_score":8.8,"headline":"Linux Kernel Improper Input Validation","id":"CVE-2013-6282","kev_date_added":"2022-09-15","published":"2013-11-19"},{"cvss_score":8.4,"headline":"Linux Kernel Heap-Based Buffer Overflow","id":"CVE-2022-0185","kev_date_added":"2024-08-21","published":"2022-02-11"},{"cvss_score":8.4,"headline":"Linux Kernel Privilege Escalation","id":"CVE-2013-2094","kev_date_added":"2022-09-15","published":"2013-05-14"},{"cvss_score":7.8,"headline":"Linux Kernel Unspecified","id":"CVE-2026-53362","kev_date_added":"2026-08-27","published":"2026-07-04"},{"cvss_score":7.8,"headline":"Linux Kernel Missing Initialization of a Variable","id":"CVE-2026-46300","kev_date_added":"2026-10-28","published":"2026-05-23"},{"cvss_score":7.8,"headline":"Linux Kernel Race Condition","id":"CVE-2025-39964","kev_date_added":"2026-09-18","published":"2025-10-13"}],"sources":[{"class":"attribution","licence":"CVE Terms of Use (MITRE)","name":"CVE List","prefix":"CVE"},{"class":"attribution","licence":"US public information, NVD API terms","name":"NVD"},{"class":"attribution","licence":"CWE Terms of Use","name":"CWE (MITRE)"},{"class":"attribution","licence":"FIRST CVSS licence","name":"CVSS (FIRST)"}],"ssvc":{"automatable":"yes","exploitation":"none","technical_impact":"partial"},"state":"PUBLISHED","updated":"2026-10-19","vendors":["Linux"]},"summary":"A deadlock in the Linux kernel MPTCP subsystem allows local attackers to cause a denial of service via recursive locking during fallback operations.","url":"https://insights.sbomify.com/CVE-2025-71126/"}