{"cve":"CVE-2021-47590","nvd":{"published":"2024-06-19T15:15:53.610","modified":"2026-06-17T04:17:49.750","status":"Modified","description":"In the Linux kernel, the following vulnerability has been resolved:\n\nmptcp: fix deadlock in __mptcp_push_pending()\n\n__mptcp_push_pending() may call mptcp_flush_join_list() with subflow\nsocket lock held. If such call hits mptcp_sockopt_sync_all() then\nsubsequently __mptcp_sockopt_sync() could try to lock the subflow\nsocket for itself, causing a deadlock.\n\nsysrq: Show Blocked State\ntask:ss-server       state:D stack:    0 pid:  938 ppid:     1 flags:0x00000000\nCall Trace:\n <TASK>\n __schedule+0x2d6/0x10c0\n ? __mod_memcg_state+0x4d/0x70\n ? csum_partial+0xd/0x20\n ? _raw_spin_lock_irqsave+0x26/0x50\n schedule+0x4e/0xc0\n __lock_sock+0x69/0x90\n ? do_wait_intr_irq+0xa0/0xa0\n __lock_sock_fast+0x35/0x50\n mptcp_sockopt_sync_all+0x38/0xc0\n __mptcp_push_pending+0x105/0x200\n mptcp_sendmsg+0x466/0x490\n sock_sendmsg+0x57/0x60\n __sys_sendto+0xf0/0x160\n ? do_wait_intr_irq+0xa0/0xa0\n ? fpregs_restore_userregs+0x12/0xd0\n __x64_sys_sendto+0x20/0x30\n do_syscall_64+0x38/0x90\n entry_SYSCALL_64_after_hwframe+0x44/0xae\nRIP: 0033:0x7f9ba546c2d0\nRSP: 002b:00007ffdc3b762d8 EFLAGS: 00000246 ORIG_RAX: 000000000000002c\nRAX: ffffffffffffffda RBX: 00007f9ba56c8060 RCX: 00007f9ba546c2d0\nRDX: 000000000000077a RSI: 0000000000e5e180 RDI: 0000000000000234\nRBP: 0000000000cc57f0 R08: 0000000000000000 R09: 0000000000000000\nR10: 0000000000000000 R11: 0000000000000246 R12: 00007f9ba56c8060\nR13: 0000000000b6ba60 R14: 0000000000cc7840 R15: 41d8685b1d7901b8\n </TASK>\n\nFix the issue by using __mptcp_flush_join_list() instead of plain\nmptcp_flush_join_list() inside __mptcp_push_pending(), as suggested by\nFlorian. The sockopt sync will be deferred to the workqueue.","cvss_v4":null,"cvss_v3":{"version":"3.1","vector":"CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H","score":5.5},"cwes":["CWE-667"],"references":["https://git.kernel.org/stable/c/23311b92755ffa9087332d1bb8c71c0f6a10cc08","https://git.kernel.org/stable/c/3d79e3756ca90f7a6087b77b62c1d9c0801e0820","https://git.kernel.org/stable/c/23311b92755ffa9087332d1bb8c71c0f6a10cc08","https://git.kernel.org/stable/c/3d79e3756ca90f7a6087b77b62c1d9c0801e0820"],"products":["linux:linux_kernel"],"source":"nvd","synced_at":"2026-10-19T21:52:00.836172422+00:00"},"epss":{"cve":"CVE-2021-47590","score":0.00156,"percentile":0.04671,"date":"2026-10-31"},"kev":null,"osv":[],"attribution":["This product uses the NVD API but is not endorsed or certified by the NVD.","EPSS scores: FIRST Exploit Prediction Scoring System, https://www.first.org/epss","Known exploited vulnerabilities: CISA Known Exploited Vulnerabilities Catalog, https://www.cisa.gov/known-exploited-vulnerabilities-catalog","Package advisories: OSV (https://osv.dev), from the GitHub Advisory Database, PyPA, Go, RustSec and other ecosystem databases, under CC-BY 4.0 or CC0","CVE records: the CVE Program's CVE List (https://www.cve.org), under its terms of use (https://www.cve.org/Legal/TermsOfUse). CVE is a registered trademark of The MITRE Corporation; this product is not affiliated with the CVE Program."]}