{"answers":{"affected":"It affects 1 product.","exploited":"There is no known exploitation of CVE-2021-47594 in the wild and no public exploit code.","fix":"Apply the vendor's patch.","what":"CVE-2021-47594 is a medium-severity vulnerability in Linux kernel, published on 19 Jun 2024. 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-2021-47594 and fix it if it is affected.\n\nWhat it is: CVE-2021-47594 is a medium-severity vulnerability in Linux kernel, published on 19 Jun 2024. 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-2021-47594 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-2021-47594/ (Markdown: https://insights.sbomify.com/CVE-2021-47594/index.md)","id":"CVE-2021-47594","markdown":"https://insights.sbomify.com/CVE-2021-47594/index.md","name":"CVE-2021-47594","record":{"aliases":["DEBIAN-CVE-2021-47594","GHSA-34pw-x3jp-c8x5","UBUNTU-CVE-2021-47594"],"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 local attacker can trigger a kernel crash by deleting an MPTCP endpoint, causing a null pointer dereference in the path manager.","user_interaction":"not_required","vuln_class":"null_dereference"},"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":[{"id":"CWE-476","name":"NULL Pointer Dereference"}],"description":"In the Linux kernel, the following vulnerability has been resolved:\n\nmptcp: never allow the PM to close a listener subflow\n\nCurrently, when deleting an endpoint the netlink PM treverses\nall the local MPTCP sockets, regardless of their status.\n\nIf an MPTCP listener socket is bound to the IP matching the\ndelete endpoint, the listener TCP socket will be closed.\nThat is unexpected, the PM should only affect data subflows.\n\nAdditionally, syzbot was able to trigger a NULL ptr dereference\ndue to the above:\n\ngeneral protection fault, probably for non-canonical address 0xdffffc0000000003: 0000 [#1] PREEMPT SMP KASAN\nKASAN: null-ptr-deref in range [0x0000000000000018-0x000000000000001f]\nCPU: 1 PID: 6550 Comm: syz-executor122 Not tainted 5.16.0-rc4-syzkaller #0\nHardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011\nRIP: 0010:__lock_acquire+0xd7d/0x54a0 kernel/locking/lockdep.c:4897\nCode: 0f 0e 41 be 01 00 00 00 0f 86 c8 00 00 00 89 05 69 cc 0f 0e e9 bd 00 00 00 48 b8 00 00 00 00 00 fc ff df 48 89 da 48 c1 ea 03 \u003c80\u003e 3c 02 00 0f 85 f3 2f 00 00 48 81 3b 20 75 17 8f 0f 84 52 f3 ff\nRSP: 0018:ffffc90001f2f818 EFLAGS: 00010016\nRAX: dffffc0000000000 RBX: 0000000000000018 RCX: 0000000000000000\nRDX: 0000000000000003 RSI: 0000000000000000 RDI: 0000000000000001\nRBP: 0000000000000000 R08: 0000000000000001 R09: 0000000000000001\nR10: 0000000000000000 R11: 000000000000000a R12: 0000000000000000\nR13: ffff88801b98d700 R14: 0000000000000000 R15: 0000000000000001\nFS:  00007f177cd3d700(0000) GS:ffff8880b9d00000(0000) knlGS:0000000000000000\nCS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033\nCR2: 00007f177cd1b268 CR3: 000000001dd55000 CR4: 0000000000350ee0\nCall Trace:\n \u003cTASK\u003e\n lock_acquire kernel/locking/lockdep.c:5637 [inline]\n lock_acquire+0x1ab/0x510 kernel/locking/lockdep.c:5602\n __raw_spin_lock_irqsave include/linux/spinlock_api_smp.h:110 [inline]\n _raw_spin_lock_irqsave+0x39/0x50 kernel/locking/spinlock.c:162\n finish_wait+0xc0/0x270 kernel/sched/wait.c:400\n inet_csk_wait_for_connect net/ipv4/inet_connection_sock.c:464 [inline]\n inet_csk_accept+0x7de/0x9d0 net/ipv4/inet_connection_sock.c:497\n mptcp_accept+0xe5/0x500 net/mptcp/protocol.c:2865\n inet_accept+0xe4/0x7b0 net/ipv4/af_inet.c:739\n mptcp_stream_accept+0x2e7/0x10e0 net/mptcp/protocol.c:3345\n do_accept+0x382/0x510 net/socket.c:1773\n __sys_accept4_file+0x7e/0xe0 net/socket.c:1816\n __sys_accept4+0xb0/0x100 net/socket.c:1846\n __do_sys_accept net/socket.c:1864 [inline]\n __se_sys_accept net/socket.c:1861 [inline]\n __x64_sys_accept+0x71/0xb0 net/socket.c:1861\n do_syscall_x64 arch/x86/entry/common.c:50 [inline]\n do_syscall_64+0x35/0xb0 arch/x86/entry/common.c:80\n entry_SYSCALL_64_after_hwframe+0x44/0xae\nRIP: 0033:0x7f177cd8b8e9\nCode: 28 00 00 00 75 05 48 83 c4 28 c3 e8 b1 14 00 00 90 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 b8 ff ff ff f7 d8 64 89 01 48\nRSP: 002b:00007f177cd3d308 EFLAGS: 00000246 ORIG_RAX: 000000000000002b\nRAX: ffffffffffffffda RBX: 00007f177ce13408 RCX: 00007f177cd8b8e9\nRDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000000000003\nRBP: 00007f177ce13400 R08: 0000000000000000 R09: 0000000000000000\nR10: 0000000000000000 R11: 0000000000000246 R12: 00007f177ce1340c\nR13: 00007f177cde1004 R14: 6d705f706374706d R15: 0000000000022000\n \u003c/TASK\u003e\n\nFix the issue explicitly skipping MPTCP socket in TCP_LISTEN\nstatus.","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: never allow the PM to close a listener subflow","id":"CVE-2021-47594","indexable":true,"kev":null,"kind":"cve","links":{"ecosystem":null,"product":"linux:linux_kernel","products":["linux:linux_kernel"],"type":"null_dereference","year":"2021"},"n_packages":0,"n_references":2,"next":{"headline":"net/sched: sch_ets: don't remove idle classes from the round-robin list","id":"CVE-2021-47595"},"packages":[],"prev":{"headline":"mptcp: clear 'kern' flag from fallback sockets","id":"CVE-2021-47593"},"products":["Linux"],"published":"2024-06-19","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":"no","exploitation":"none","technical_impact":"partial"},"state":"PUBLISHED","updated":"2026-05-11","vendors":["Linux"]},"summary":"A local attacker can trigger a kernel crash by deleting an MPTCP endpoint, causing a null pointer dereference in the path manager.","url":"https://insights.sbomify.com/CVE-2021-47594/"}