{"answers":{"affected":"It affects 1 product.","exploited":"There is no known exploitation of CVE-2025-21706 in the wild and no public exploit code.","fix":"Apply the vendor's patch.","what":"CVE-2025-21706 is a medium-severity denial of service vulnerability in Linux kernel, published on 27 Feb 2025. It can only be exploited from the same machine or local network, with no action from the victim."},"fix_prompt":"Check this codebase for CVE-2025-21706 and fix it if it is affected.\n\nWhat it is: CVE-2025-21706 is a medium-severity denial of service vulnerability in Linux kernel, published on 27 Feb 2025. It can only be exploited from the same machine or local network, with no action from the victim.\nExploitation: There is no known exploitation of CVE-2025-21706 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-2025-21706/ (Markdown: https://insights.sbomify.com/CVE-2025-21706/index.md)","id":"CVE-2025-21706","markdown":"https://insights.sbomify.com/CVE-2025-21706/index.md","name":"CVE-2025-21706","record":{"aliases":["BELL-CVE-2025-21706","DEBIAN-CVE-2025-21706","GHSA-fx65-xwxc-78xx","ROOT-OS-UBUNTU-2404-CVE-2025-21706","UBUNTU-CVE-2025-21706"],"analysis":{"component_type":"kernel","fix_type":"patch","impacts":["denial_of_service"],"network_reachable":"adjacent_or_local","non_default_config":false,"product_category":"Linux kernel","requires_auth":"low_privilege","summary":"A logic error in the Linux kernel's MPTCP path manager allows triggering a kernel warning, potentially leading to a denial of service.","user_interaction":"not_required","vuln_class":"denial_of_service"},"analysis_generated_by":"qwen3.8-flash-next","assigner":"Linux","cpe":[{"product":"linux_kernel","vendor":"linux"}],"cvss":{"score":5.5,"severity":"medium","source":"nvd","vector":"CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H","version":"3.1"},"cwes":[],"description":"In the Linux kernel, the following vulnerability has been resolved:\n\nmptcp: pm: only set fullmesh for subflow endp\n\nWith the in-kernel path-manager, it is possible to change the 'fullmesh'\nflag. The code in mptcp_pm_nl_fullmesh() expects to change it only on\n'subflow' endpoints, to recreate more or less subflows using the linked\naddress.\n\nUnfortunately, the set_flags() hook was a bit more permissive, and\nallowed 'implicit' endpoints to get the 'fullmesh' flag while it is not\nallowed before.\n\nThat's what syzbot found, triggering the following warning:\n\n  WARNING: CPU: 0 PID: 6499 at net/mptcp/pm_netlink.c:1496 __mark_subflow_endp_available net/mptcp/pm_netlink.c:1496 [inline]\n  WARNING: CPU: 0 PID: 6499 at net/mptcp/pm_netlink.c:1496 mptcp_pm_nl_fullmesh net/mptcp/pm_netlink.c:1980 [inline]\n  WARNING: CPU: 0 PID: 6499 at net/mptcp/pm_netlink.c:1496 mptcp_nl_set_flags net/mptcp/pm_netlink.c:2003 [inline]\n  WARNING: CPU: 0 PID: 6499 at net/mptcp/pm_netlink.c:1496 mptcp_pm_nl_set_flags+0x974/0xdc0 net/mptcp/pm_netlink.c:2064\n  Modules linked in:\n  CPU: 0 UID: 0 PID: 6499 Comm: syz.1.413 Not tainted 6.13.0-rc5-syzkaller-00172-gd1bf27c4e176 #0\n  Hardware name: Google Compute Engine/Google Compute Engine, BIOS Google 09/13/2024\n  RIP: 0010:__mark_subflow_endp_available net/mptcp/pm_netlink.c:1496 [inline]\n  RIP: 0010:mptcp_pm_nl_fullmesh net/mptcp/pm_netlink.c:1980 [inline]\n  RIP: 0010:mptcp_nl_set_flags net/mptcp/pm_netlink.c:2003 [inline]\n  RIP: 0010:mptcp_pm_nl_set_flags+0x974/0xdc0 net/mptcp/pm_netlink.c:2064\n  Code: 01 00 00 49 89 c5 e8 fb 45 e8 f5 e9 b8 fc ff ff e8 f1 45 e8 f5 4c 89 f7 be 03 00 00 00 e8 44 1d 0b f9 eb a0 e8 dd 45 e8 f5 90 \u003c0f\u003e 0b 90 e9 17 ff ff ff 89 d9 80 e1 07 38 c1 0f 8c c9 fc ff ff 48\n  RSP: 0018:ffffc9000d307240 EFLAGS: 00010293\n  RAX: ffffffff8bb72e03 RBX: 0000000000000000 RCX: ffff88807da88000\n  RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000000000000\n  RBP: ffffc9000d307430 R08: ffffffff8bb72cf0 R09: 1ffff1100b842a5e\n  R10: dffffc0000000000 R11: ffffed100b842a5f R12: ffff88801e2e5ac0\n  R13: ffff88805c214800 R14: ffff88805c2152e8 R15: 1ffff1100b842a5d\n  FS:  00005555619f6500(0000) GS:ffff8880b8600000(0000) knlGS:0000000000000000\n  CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033\n  CR2: 0000000020002840 CR3: 00000000247e6000 CR4: 00000000003526f0\n  DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000\n  DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400\n  Call Trace:\n   \u003cTASK\u003e\n   genl_family_rcv_msg_doit net/netlink/genetlink.c:1115 [inline]\n   genl_family_rcv_msg net/netlink/genetlink.c:1195 [inline]\n   genl_rcv_msg+0xb14/0xec0 net/netlink/genetlink.c:1210\n   netlink_rcv_skb+0x1e3/0x430 net/netlink/af_netlink.c:2542\n   genl_rcv+0x28/0x40 net/netlink/genetlink.c:1219\n   netlink_unicast_kernel net/netlink/af_netlink.c:1321 [inline]\n   netlink_unicast+0x7f6/0x990 net/netlink/af_netlink.c:1347\n   netlink_sendmsg+0x8e4/0xcb0 net/netlink/af_netlink.c:1891\n   sock_sendmsg_nosec net/socket.c:711 [inline]\n   __sock_sendmsg+0x221/0x270 net/socket.c:726\n   ____sys_sendmsg+0x52a/0x7e0 net/socket.c:2583\n   ___sys_sendmsg net/socket.c:2637 [inline]\n   __sys_sendmsg+0x269/0x350 net/socket.c:2669\n   do_syscall_x64 arch/x86/entry/common.c:52 [inline]\n   do_syscall_64+0xf3/0x230 arch/x86/entry/common.c:83\n   entry_SYSCALL_64_after_hwframe+0x77/0x7f\n  RIP: 0033:0x7f5fe8785d29\n  Code: ff ff c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 40 00 48 89 f8 48 89 f7 48 89 d6 48 89 ca 4d 89 c2 4d 89 c8 4c 8b 4c 24 08 0f 05 \u003c48\u003e 3d 01 f0 ff ff 73 01 c3 48 c7 c1 a8 ff ff ff f7 d8 64 89 01 48\n  RSP: 002b:00007fff571f5558 EFLAGS: 00000246 ORIG_RAX: 000000000000002e\n  RAX: ffffffffffffffda RBX: 00007f5fe8975fa0 RCX: 00007f5fe8785d29\n  RDX: 0000000000000000 RSI: 0000000020000480 RDI: 0000000000000007\n  RBP: 00007f5fe8801b08 R08: 0000000000000000 R09: 0000000000000000\n  R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000\n  R13: 00007f5fe8975fa0 R14: 00007f5fe8975fa0 R15: 000000\n---truncated---","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: pm: only set fullmesh for subflow endp","id":"CVE-2025-21706","indexable":true,"kev":null,"kind":"cve","links":{"ecosystem":null,"product":"linux:linux_kernel","products":["linux:linux_kernel"],"type":"denial_of_service","year":"2025"},"n_packages":0,"n_references":5,"next":{"headline":"mptcp: consolidate suboption status","id":"CVE-2025-21707"},"packages":[],"prev":{"headline":"mptcp: handle fastopen disconnect correctly","id":"CVE-2025-21705"},"products":["Linux"],"published":"2025-02-27","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":"FIRST CVSS licence","name":"CVSS (FIRST)"}],"ssvc":{"automatable":null,"exploitation":null,"technical_impact":null},"state":"PUBLISHED","updated":"2026-10-15","vendors":["Linux"]},"summary":"A logic error in the Linux kernel's MPTCP path manager allows triggering a kernel warning, potentially leading to a denial of service.","url":"https://insights.sbomify.com/CVE-2025-21706/"}