{"cve":"CVE-2024-35870","nvd":{"published":"2024-05-19T09:15:08.427","modified":"2026-08-04T11:18:03.407","status":"Modified","description":"In the Linux kernel, the following vulnerability has been resolved:\n\nsmb: client: fix UAF in smb2_reconnect_server()\n\nThe UAF bug is due to smb2_reconnect_server() accessing a session that\nis already being teared down by another thread that is executing\n__cifs_put_smb_ses().  This can happen when (a) the client has\nconnection to the server but no session or (b) another thread ends up\nsetting @ses->ses_status again to something different than\nSES_EXITING.\n\nTo fix this, we need to make sure to unconditionally set\n@ses->ses_status to SES_EXITING and prevent any other threads from\nsetting a new status while we're still tearing it down.\n\nThe following can be reproduced by adding some delay to right after\nthe ipc is freed in __cifs_put_smb_ses() - which will give\nsmb2_reconnect_server() worker a chance to run and then accessing\n@ses->ipc:\n\nkinit ...\nmount.cifs //srv/share /mnt/1 -o sec=krb5,nohandlecache,echo_interval=10\n[disconnect srv]\nls /mnt/1 &>/dev/null\nsleep 30\nkdestroy\n[reconnect srv]\nsleep 10\numount /mnt/1\n...\nCIFS: VFS: Verify user has a krb5 ticket and keyutils is installed\nCIFS: VFS: \\\\srv Send error in SessSetup = -126\nCIFS: VFS: Verify user has a krb5 ticket and keyutils is installed\nCIFS: VFS: \\\\srv Send error in SessSetup = -126\ngeneral protection fault, probably for non-canonical address\n0x6b6b6b6b6b6b6b6b: 0000 [#1] PREEMPT SMP NOPTI\nCPU: 3 PID: 50 Comm: kworker/3:1 Not tainted 6.9.0-rc2 #1\nHardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS 1.16.3-1.fc39\n04/01/2014\nWorkqueue: cifsiod smb2_reconnect_server [cifs]\nRIP: 0010:__list_del_entry_valid_or_report+0x33/0xf0\nCode: 4f 08 48 85 d2 74 42 48 85 c9 74 59 48 b8 00 01 00 00 00 00 ad\nde 48 39 c2 74 61 48 b8 22 01 00 00 00 00 74 69 <48> 8b 01 48 39 f8 75\n7b 48 8b 72 08 48 39 c6 0f 85 88 00 00 00 b8\nRSP: 0018:ffffc900001bfd70 EFLAGS: 00010a83\nRAX: dead000000000122 RBX: ffff88810da53838 RCX: 6b6b6b6b6b6b6b6b\nRDX: 6b6b6b6b6b6b6b6b RSI: ffffffffc02f6878 RDI: ffff88810da53800\nRBP: ffff88810da53800 R08: 0000000000000001 R09: 0000000000000000\nR10: 0000000000000000 R11: 0000000000000001 R12: ffff88810c064000\nR13: 0000000000000001 R14: ffff88810c064000 R15: ffff8881039cc000\nFS: 0000000000000000(0000) GS:ffff888157c00000(0000)\nknlGS:0000000000000000\nCS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033\nCR2: 00007fe3728b1000 CR3: 000000010caa4000 CR4: 0000000000750ef0\nPKRU: 55555554\nCall Trace:\n <TASK>\n ? die_addr+0x36/0x90\n ? exc_general_protection+0x1c1/0x3f0\n ? asm_exc_general_protection+0x26/0x30\n ? __list_del_entry_valid_or_report+0x33/0xf0\n __cifs_put_smb_ses+0x1ae/0x500 [cifs]\n smb2_reconnect_server+0x4ed/0x710 [cifs]\n process_one_work+0x205/0x6b0\n worker_thread+0x191/0x360\n ? __pfx_worker_thread+0x10/0x10\n kthread+0xe2/0x110\n ? __pfx_kthread+0x10/0x10\n ret_from_fork+0x34/0x50\n ? __pfx_kthread+0x10/0x10\n ret_from_fork_asm+0x1a/0x30\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:H/I:H/A:H","score":9.8},"cwes":["CWE-416"],"references":["https://git.kernel.org/stable/c/24a9799aa8efecd0eb55a75e35f9d8e6400063aa","https://git.kernel.org/stable/c/45f2beda1f1bc3d962ec07db1ccc3197c25499a5","https://git.kernel.org/stable/c/6202996a1c1887e83d0b3b0fcd86d0e5e6910ea0","https://git.kernel.org/stable/c/755fe68cd4b59e1d2a2dd3286177fd4404f57fed","https://git.kernel.org/stable/c/24a9799aa8efecd0eb55a75e35f9d8e6400063aa"],"products":["linux:linux_kernel"],"source":"nvd","synced_at":"2026-10-19T21:50:30.954589733+00:00"},"epss":{"cve":"CVE-2024-35870","score":0.00618,"percentile":0.49653,"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."]}