{"cve":"CVE-2026-43029","nvd":{"published":"2026-05-01T15:16:47.427","modified":"2026-06-17T10:48:47.810","status":"Analyzed","description":"In the Linux kernel, the following vulnerability has been resolved:\n\nmptcp: fix soft lockup in mptcp_recvmsg()\n\nsyzbot reported a soft lockup in mptcp_recvmsg() [0].\n\nWhen receiving data with MSG_PEEK | MSG_WAITALL flags, the skb is not\nremoved from the sk_receive_queue. This causes sk_wait_data() to always\nfind available data and never perform actual waiting, leading to a soft\nlockup.\n\nFix this by adding a 'last' parameter to track the last peeked skb.\nThis allows sk_wait_data() to make informed waiting decisions and prevent\ninfinite loops when MSG_PEEK is used.\n\n[0]:\nwatchdog: BUG: soft lockup - CPU#2 stuck for 156s! [server:1963]\nModules linked in:\nCPU: 2 UID: 0 PID: 1963 Comm: server Not tainted 6.19.0-rc8 #61 PREEMPT(none)\nHardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.15.0-1 04/01/2014\nRIP: 0010:sk_wait_data+0x15/0x190\nCode: 80 00 00 00 00 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 f3 0f 1e fa 41 56 41 55 41 54 49 89 f4 55 48 89 d5 53 48 89 fb <48> 83 ec 30 65 48 8b 05 17 a4 6b 01 48 89 44 24 28 31 c0 65 48 8b\nRSP: 0018:ffffc90000603ca0 EFLAGS: 00000246\nRAX: 0000000000000000 RBX: ffff888102bf0800 RCX: 0000000000000001\nRDX: 0000000000000000 RSI: ffffc90000603d18 RDI: ffff888102bf0800\nRBP: 0000000000000000 R08: 0000000000000002 R09: 0000000000000101\nR10: 0000000000000000 R11: 0000000000000075 R12: ffffc90000603d18\nR13: ffff888102bf0800 R14: ffff888102bf0800 R15: 0000000000000000\nFS:  00007f6e38b8c4c0(0000) GS:ffff8881b877e000(0000) knlGS:0000000000000000\nCS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033\nCR2: 000055aa7bff1680 CR3: 0000000105cbe000 CR4: 00000000000006f0\nCall Trace:\n <TASK>\n mptcp_recvmsg+0x547/0x8c0 net/mptcp/protocol.c:2329\n inet_recvmsg+0x11f/0x130 net/ipv4/af_inet.c:891\n sock_recvmsg+0x94/0xc0 net/socket.c:1100\n __sys_recvfrom+0xb2/0x130 net/socket.c:2256\n __x64_sys_recvfrom+0x1f/0x30 net/socket.c:2267\n do_syscall_64+0x59/0x2d0 arch/x86/entry/syscall_64.c:94\n entry_SYSCALL_64_after_hwframe+0x76/0x7e arch/x86/entry/entry_64.S:131\nRIP: 0033:0x7f6e386a4a1d\nCode: 0f 1f 84 00 00 00 00 00 0f 1f 44 00 00 48 8d 05 f1 de 2c 00 41 89 ca 8b 00 85 c0 75 20 45 31 c9 45 31 c0 b8 2d 00 00 00 0f 05 <48> 3d 00 f0 ff ff 77 6b f3 c3 66 0f 1f 84 00 00 00 00 00 41 56 41\nRSP: 002b:00007ffc3c4bb078 EFLAGS: 00000246 ORIG_RAX: 000000000000002d\nRAX: ffffffffffffffda RBX: 000000000000861e RCX: 00007f6e386a4a1d\nRDX: 00000000000003ff RSI: 00007ffc3c4bb150 RDI: 0000000000000004\nRBP: 00007ffc3c4bb570 R08: 0000000000000000 R09: 0000000000000000\nR10: 0000000000000103 R11: 0000000000000246 R12: 00005605dbc00be0\nR13: 00007ffc3c4bb650 R14: 0000000000000000 R15: 0000000000000000\n </TASK>","cvss_v4":null,"cvss_v3":{"version":"3.1","vector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H","score":7.5},"cwes":["CWE-667"],"references":["https://git.kernel.org/stable/c/58b58b9ba89c43914eea90c18928e51852d10c24","https://git.kernel.org/stable/c/5dd8025a49c268ab6b94d978532af3ad341132a7","https://git.kernel.org/stable/c/de3c248d1b69eaefa2d5b3da4005936dcf590f1b"],"products":["linux:linux_kernel"],"source":"nvd","synced_at":"2026-10-19T22:33:09.003606135+00:00"},"epss":{"cve":"CVE-2026-43029","score":0.00329,"percentile":0.26083,"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."]}