{"answers":{"affected":"It affects 1 product.","exploited":"There is no known exploitation of CVE-2026-23321 in the wild and no public exploit code.","fix":"Apply the vendor's patch.","what":"CVE-2026-23321 is a medium-severity denial of service vulnerability in Linux kernel, published on 25 Mar 2026. 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-2026-23321 and fix it if it is affected.\n\nWhat it is: CVE-2026-23321 is a medium-severity denial of service vulnerability in Linux kernel, published on 25 Mar 2026. 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-2026-23321 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-2026-23321/ (Markdown: https://insights.sbomify.com/CVE-2026-23321/index.md)","id":"CVE-2026-23321","markdown":"https://insights.sbomify.com/CVE-2026-23321/index.md","name":"CVE-2026-23321","record":{"aliases":["BELL-CVE-2026-23321","DEBIAN-CVE-2026-23321","GHSA-cp65-xq47-m66j","ROOT-OS-DEBIAN-12-CVE-2026-23321","ROOT-OS-DEBIAN-13-CVE-2026-23321","ROOT-OS-UBUNTU-2404-CVE-2026-23321","UBUNTU-CVE-2026-23321"],"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 can trigger a kernel warning and potential denial of service when removing addresses.","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: in-kernel: always mark signal+subflow endp as used\n\nSyzkaller managed to find a combination of actions that was generating\nthis warning:\n\n  msk-\u003epm.local_addr_used == 0\n  WARNING: net/mptcp/pm_kernel.c:1071 at __mark_subflow_endp_available net/mptcp/pm_kernel.c:1071 [inline], CPU#1: syz.2.17/961\n  WARNING: net/mptcp/pm_kernel.c:1071 at mptcp_nl_remove_subflow_and_signal_addr net/mptcp/pm_kernel.c:1103 [inline], CPU#1: syz.2.17/961\n  WARNING: net/mptcp/pm_kernel.c:1071 at mptcp_pm_nl_del_addr_doit+0x81d/0x8f0 net/mptcp/pm_kernel.c:1210, CPU#1: syz.2.17/961\n  Modules linked in:\n  CPU: 1 UID: 0 PID: 961 Comm: syz.2.17 Not tainted 6.19.0-08368-gfafda3b4b06b #22 PREEMPT(full)\n  Hardware name: QEMU Ubuntu 25.10 PC v2 (i440FX + PIIX, + 10.1 machine, 1996), BIOS 1.17.0-debian-1.17.0-1build1 04/01/2014\n  RIP: 0010:__mark_subflow_endp_available net/mptcp/pm_kernel.c:1071 [inline]\n  RIP: 0010:mptcp_nl_remove_subflow_and_signal_addr net/mptcp/pm_kernel.c:1103 [inline]\n  RIP: 0010:mptcp_pm_nl_del_addr_doit+0x81d/0x8f0 net/mptcp/pm_kernel.c:1210\n  Code: 89 c5 e8 46 30 6f fe e9 21 fd ff ff 49 83 ed 80 e8 38 30 6f fe 4c 89 ef be 03 00 00 00 e8 db 49 df fe eb ac e8 24 30 6f fe 90 \u003c0f\u003e 0b 90 e9 1d ff ff ff e8 16 30 6f fe eb 05 e8 0f 30 6f fe e8 9a\n  RSP: 0018:ffffc90001663880 EFLAGS: 00010293\n  RAX: ffffffff82de1a6c RBX: 0000000000000000 RCX: ffff88800722b500\n  RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000000000000\n  RBP: ffff8880158b22d0 R08: 0000000000010425 R09: ffffffffffffffff\n  R10: ffffffff82de18ba R11: 0000000000000000 R12: ffff88800641a640\n  R13: ffff8880158b1880 R14: ffff88801ec3c900 R15: ffff88800641a650\n  FS:  00005555722c3500(0000) GS:ffff8880f909d000(0000) knlGS:0000000000000000\n  CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033\n  CR2: 00007f66346e0f60 CR3: 000000001607c000 CR4: 0000000000350ef0\n  Call Trace:\n   \u003cTASK\u003e\n   genl_family_rcv_msg_doit+0x117/0x180 net/netlink/genetlink.c:1115\n   genl_family_rcv_msg net/netlink/genetlink.c:1195 [inline]\n   genl_rcv_msg+0x3a8/0x3f0 net/netlink/genetlink.c:1210\n   netlink_rcv_skb+0x16d/0x240 net/netlink/af_netlink.c:2550\n   genl_rcv+0x28/0x40 net/netlink/genetlink.c:1219\n   netlink_unicast_kernel net/netlink/af_netlink.c:1318 [inline]\n   netlink_unicast+0x3e9/0x4c0 net/netlink/af_netlink.c:1344\n   netlink_sendmsg+0x4aa/0x5b0 net/netlink/af_netlink.c:1894\n   sock_sendmsg_nosec net/socket.c:727 [inline]\n   __sock_sendmsg+0xc9/0xf0 net/socket.c:742\n   ____sys_sendmsg+0x272/0x3b0 net/socket.c:2592\n   ___sys_sendmsg+0x2de/0x320 net/socket.c:2646\n   __sys_sendmsg net/socket.c:2678 [inline]\n   __do_sys_sendmsg net/socket.c:2683 [inline]\n   __se_sys_sendmsg net/socket.c:2681 [inline]\n   __x64_sys_sendmsg+0x110/0x1a0 net/socket.c:2681\n   do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]\n   do_syscall_64+0x143/0x440 arch/x86/entry/syscall_64.c:94\n   entry_SYSCALL_64_after_hwframe+0x77/0x7f\n  RIP: 0033:0x7f66346f826d\n  Code: ff c3 66 2e 0f 1f 84 00 00 00 00 00 90 f3 0f 1e fa 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 e8 ff ff ff f7 d8 64 89 01 48\n  RSP: 002b:00007ffc83d8bdc8 EFLAGS: 00000246 ORIG_RAX: 000000000000002e\n  RAX: ffffffffffffffda RBX: 00007f6634985fa0 RCX: 00007f66346f826d\n  RDX: 00000000040000b0 RSI: 0000200000000740 RDI: 0000000000000007\n  RBP: 0000000000000000 R08: 0000000000000000 R09: 0000000000000000\n  R10: 0000000000000000 R11: 0000000000000246 R12: 00007f6634985fa8\n  R13: 00007f6634985fac R14: 0000000000000000 R15: 0000000000001770\n   \u003c/TASK\u003e\n\nThe actions that caused that seem to be:\n\n - Set the MPTCP subflows limit to 0\n - Create an MPTCP endpoint with both the 'signal' and 'subflow' flags\n - Create a new MPTCP connection from a different address: an ADD_ADDR\n   linked to the MPTCP endpoint will be sent ('signal' flag), but no\n   subflows is initiated ('subflow' flag)\n - Remove the MPTCP endpoint\n\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: in-kernel: always mark signal+subflow endp as used","id":"CVE-2026-23321","indexable":true,"kev":null,"kind":"cve","links":{"ecosystem":null,"product":"linux:linux_kernel","products":["linux:linux_kernel"],"type":"denial_of_service","year":"2026"},"n_packages":0,"n_references":6,"next":{"headline":"ipmi: Fix use-after-free and list corruption on sender error","id":"CVE-2026-23322"},"packages":[],"prev":{"headline":"This CVE ID has been rejected or withdrawn by its CVE Numbering Authority.","id":"CVE-2026-23320"},"products":["Linux"],"published":"2026-03-25","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 can trigger a kernel warning and potential denial of service when removing addresses.","url":"https://insights.sbomify.com/CVE-2026-23321/"}