{"cve":"CVE-2024-36889","nvd":{"published":"2024-05-30T16:15:12.410","modified":"2026-06-17T07:37:16.990","status":"Analyzed","description":"In the Linux kernel, the following vulnerability has been resolved:\n\nmptcp: ensure snd_nxt is properly initialized on connect\n\nChristoph reported a splat hinting at a corrupted snd_una:\n\n  WARNING: CPU: 1 PID: 38 at net/mptcp/protocol.c:1005 __mptcp_clean_una+0x4b3/0x620 net/mptcp/protocol.c:1005\n  Modules linked in:\n  CPU: 1 PID: 38 Comm: kworker/1:1 Not tainted 6.9.0-rc1-gbbeac67456c9 #59\n  Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.11.0-2.el7 04/01/2014\n  Workqueue: events mptcp_worker\n  RIP: 0010:__mptcp_clean_una+0x4b3/0x620 net/mptcp/protocol.c:1005\n  Code: be 06 01 00 00 bf 06 01 00 00 e8 a8 12 e7 fe e9 00 fe ff ff e8\n  \t8e 1a e7 fe 0f b7 ab 3e 02 00 00 e9 d3 fd ff ff e8 7d 1a e7 fe\n  \t<0f> 0b 4c 8b bb e0 05 00 00 e9 74 fc ff ff e8 6a 1a e7 fe 0f 0b e9\n  RSP: 0018:ffffc9000013fd48 EFLAGS: 00010293\n  RAX: 0000000000000000 RBX: ffff8881029bd280 RCX: ffffffff82382fe4\n  RDX: ffff8881003cbd00 RSI: ffffffff823833c3 RDI: 0000000000000001\n  RBP: 0000000000000000 R08: 0000000000000001 R09: 0000000000000000\n  R10: 0000000000000000 R11: fefefefefefefeff R12: ffff888138ba8000\n  R13: 0000000000000106 R14: ffff8881029bd908 R15: ffff888126560000\n  FS:  0000000000000000(0000) GS:ffff88813bd00000(0000) knlGS:0000000000000000\n  CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033\n  CR2: 00007f604a5dae38 CR3: 0000000101dac002 CR4: 0000000000170ef0\n  Call Trace:\n   <TASK>\n   __mptcp_clean_una_wakeup net/mptcp/protocol.c:1055 [inline]\n   mptcp_clean_una_wakeup net/mptcp/protocol.c:1062 [inline]\n   __mptcp_retrans+0x7f/0x7e0 net/mptcp/protocol.c:2615\n   mptcp_worker+0x434/0x740 net/mptcp/protocol.c:2767\n   process_one_work+0x1e0/0x560 kernel/workqueue.c:3254\n   process_scheduled_works kernel/workqueue.c:3335 [inline]\n   worker_thread+0x3c7/0x640 kernel/workqueue.c:3416\n   kthread+0x121/0x170 kernel/kthread.c:388\n   ret_from_fork+0x44/0x50 arch/x86/kernel/process.c:147\n   ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:243\n   </TASK>\n\nWhen fallback to TCP happens early on a client socket, snd_nxt\nis not yet initialized and any incoming ack will copy such value\ninto snd_una. If the mptcp worker (dumbly) tries mptcp-level\nre-injection after such ack, that would unconditionally trigger a send\nbuffer cleanup using 'bad' snd_una values.\n\nWe could easily disable re-injection for fallback sockets, but such\ndumb behavior already helped catching a few subtle issues and a very\nlow to zero impact in practice.\n\nInstead address the issue always initializing snd_nxt (and write_seq,\nfor consistency) at connect time.","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":[],"references":["https://git.kernel.org/stable/c/39ca83ed73db9edcc6d70c0dc7a73085a4725012","https://git.kernel.org/stable/c/592f69b41766d366dbb8ff4ef5a67c4396527bbe","https://git.kernel.org/stable/c/99951b62bf20cec9247f633a3bea898338b9e5b4","https://git.kernel.org/stable/c/aa0c07c1f20e05b30019bff083ec43665536f06f","https://git.kernel.org/stable/c/dc941fec0719d0471a5902424d6b2a17df233193"],"products":["debian:debian_linux","linux:linux_kernel"],"source":"nvd","synced_at":"2026-10-19T21:51:20.603330631+00:00"},"epss":{"cve":"CVE-2024-36889","score":0.00267,"percentile":0.18866,"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."]}