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CVE-2026-23427— ksmbd: fix use-after-free in durable v2 replay of active file handles

Quick assessment

Affected
Linux Linux
Exploitation
No confirmed in-the-wild exploitation; assess based on exposure
Recommended action
Check the vendor advisory and references for a fixed version. If immediate upgrade is impossible, restrict exposure and increase monitoring.

Linux kernel是美国Linux基金会的开源操作系统Linux所使用的内核。 Linux kernel存在安全漏洞，该漏洞源于持久句柄v2重放中文件句柄连接覆盖不当，可能导致释放后重用。

CVSS 9.8 · Critical EPSS 0.29% · P20

Affected Version Matrix 13

VendorProduct Version RangeStatus
Linux Linux 8df4bcdb0a4232192b2445256c39b787d58ef14d< b0158d9d6f4ec5941e49a0b812735db2844f9975 affected
c8efcc786146a951091588e5fa7e3c754850cb3c< 568a25fd7bcdfb2790f7d42aa2a440dca4435c96 affected
c8efcc786146a951091588e5fa7e3c754850cb3c< a5828c14a9e3d5eeed0bcc0a58f0f3fbca0cdcb2 affected
c8efcc786146a951091588e5fa7e3c754850cb3c< 9b0792c3eacf01e67f356d6ef9707b0ae5022419 affected
c8efcc786146a951091588e5fa7e3c754850cb3c< b425e4d0eb321a1116ddbf39636333181675d8f4 affected
6.6.32< 6.6.130 affected
6.9 affected
< 6.9 unaffected
… +5 more rows
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I. Basic Information for CVE-2026-23427

Vulnerability Information
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Vulnerability Title
ksmbd: fix use-after-free in durable v2 replay of active file handles
Source: CVE Program / CVE List V5
Vulnerability Description
In the Linux kernel, the following vulnerability has been resolved: ksmbd: fix use-after-free in durable v2 replay of active file handles parse_durable_handle_context() unconditionally assigns dh_info->fp->conn to the current connection when handling a DURABLE_REQ_V2 context with SMB2_FLAGS_REPLAY_OPERATION. ksmbd_lookup_fd_cguid() does not filter by fp->conn, so it returns file handles that are already actively connected. The unconditional overwrite replaces fp->conn, and when the overwriting connection is subsequently freed, __ksmbd_close_fd() dereferences the stale fp->conn via spin_lock(&fp->conn->llist_lock), causing a use-after-free. KASAN report: [ 7.349357] ================================================================== [ 7.349607] BUG: KASAN: slab-use-after-free in _raw_spin_lock+0x75/0xe0 [ 7.349811] Write of size 4 at addr ffff8881056ac18c by task kworker/1:2/108 [ 7.350010] [ 7.350064] CPU: 1 UID: 0 PID: 108 Comm: kworker/1:2 Not tainted 7.0.0-rc3+ #58 PREEMPTLAZY [ 7.350068] Hardware name: QEMU Ubuntu 24.04 PC v2 (i440FX + PIIX, arch_caps fix, 1996), BIOS 1.16.3-debian-1.16.3-2 04/01/2014 [ 7.350070] Workqueue: ksmbd-io handle_ksmbd_work [ 7.350083] Call Trace: [ 7.350087] <TASK> [ 7.350087] dump_stack_lvl+0x64/0x80 [ 7.350094] print_report+0xce/0x660 [ 7.350100] ? __pfx__raw_spin_lock_irqsave+0x10/0x10 [ 7.350101] ? __pfx___mod_timer+0x10/0x10 [ 7.350106] ? _raw_spin_lock+0x75/0xe0 [ 7.350108] kasan_report+0xce/0x100 [ 7.350109] ? _raw_spin_lock+0x75/0xe0 [ 7.350114] kasan_check_range+0x105/0x1b0 [ 7.350116] _raw_spin_lock+0x75/0xe0 [ 7.350118] ? __pfx__raw_spin_lock+0x10/0x10 [ 7.350119] ? __call_rcu_common.constprop.0+0x25e/0x780 [ 7.350125] ? close_id_del_oplock+0x2cc/0x4e0 [ 7.350128] __ksmbd_close_fd+0x27f/0xaf0 [ 7.350131] ksmbd_close_fd+0x135/0x1b0 [ 7.350133] smb2_close+0xb19/0x15b0 [ 7.350142] ? __pfx_smb2_close+0x10/0x10 [ 7.350143] ? xas_load+0x18/0x270 [ 7.350146] ? _raw_spin_lock+0x84/0xe0 [ 7.350148] ? __pfx__raw_spin_lock+0x10/0x10 [ 7.350150] ? _raw_spin_unlock+0xe/0x30 [ 7.350151] ? ksmbd_smb2_check_message+0xeb2/0x24c0 [ 7.350153] ? ksmbd_tree_conn_lookup+0xcd/0xf0 [ 7.350154] handle_ksmbd_work+0x40f/0x1080 [ 7.350156] process_one_work+0x5fa/0xef0 [ 7.350162] ? assign_work+0x122/0x3e0 [ 7.350163] worker_thread+0x54b/0xf70 [ 7.350165] ? __pfx_worker_thread+0x10/0x10 [ 7.350166] kthread+0x346/0x470 [ 7.350170] ? recalc_sigpending+0x19b/0x230 [ 7.350176] ? __pfx_kthread+0x10/0x10 [ 7.350178] ret_from_fork+0x4fb/0x6c0 [ 7.350183] ? __pfx_ret_from_fork+0x10/0x10 [ 7.350185] ? __switch_to+0x36c/0xbe0 [ 7.350188] ? __pfx_kthread+0x10/0x10 [ 7.350190] ret_from_fork_asm+0x1a/0x30 [ 7.350197] </TASK> [ 7.350197] [ 7.355160] Allocated by task 123: [ 7.355261] kasan_save_stack+0x33/0x60 [ 7.355373] kasan_save_track+0x14/0x30 [ 7.355484] __kasan_kmalloc+0x8f/0xa0 [ 7.355593] ksmbd_conn_alloc+0x44/0x6d0 [ 7.355711] ksmbd_kthread_fn+0x243/0xd70 [ 7.355839] kthread+0x346/0x470 [ 7.355942] ret_from_fork+0x4fb/0x6c0 [ 7.356051] ret_from_fork_asm+0x1a/0x30 [ 7.356164] [ 7.356214] Freed by task 134: [ 7.356305] kasan_save_stack+0x33/0x60 [ 7.356416] kasan_save_track+0x14/0x30 [ 7.356527] kasan_save_free_info+0x3b/0x60 [ 7.356646] __kasan_slab_free+0x43/0x70 [ 7.356761] kfree+0x1ca/0x430 [ 7.356862] ksmbd_tcp_disconnect+0x59/0xe0 [ 7.356993] ksmbd_conn_handler_loop+0x77e/0xd40 [ 7.357138] kthread+0x346/0x470 [ 7.357240] ret_from_fork+0x4fb/0x6c0 [ 7.357350] ret_from_fork_asm+0x1a/0x30 [ 7.357463] [ 7.357513] The buggy address belongs to the object at ffff8881056ac000 [ 7.357513] which belongs to the cache kmalloc-1k of size 1024 [ 7.357857] The buggy address is located 396 bytes inside of [ 7.357857] freed 1024-byte region ---truncated---
Source: CVE Program / CVE List V5
CVSS Information
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
Source: CVE Program / CVE List V5
Vulnerability Type
N/A
Source: CVE Program / CVE List V5
Vulnerability Title
Linux kernel 安全漏洞
Source: CNNVD (China National Vulnerability Database)
Vulnerability Description
Linux kernel是美国Linux基金会的开源操作系统Linux所使用的内核。 Linux kernel存在安全漏洞，该漏洞源于持久句柄v2重放中文件句柄连接覆盖不当，可能导致释放后重用。
Source: CNNVD (China National Vulnerability Database)
CVSS Information
N/A
Source: CNNVD (China National Vulnerability Database)
Vulnerability Type
N/A
Source: CNNVD (China National Vulnerability Database)

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Affected Products

Vendor Product Affected Versions CPE Subscribe
Linux Linux 8df4bcdb0a4232192b2445256c39b787d58ef14d ~ b0158d9d6f4ec5941e49a0b812735db2844f9975 -
Linux Linux 6.9 -

II. Public POCs for CVE-2026-23427

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III. Intelligence Information for CVE-2026-23427

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Same Patch Batch · Linux · 2026-04-03 · 71 CVEs total

CVE-2026-31402 9.8 CRITICAL nfsd: fix heap overflow in NFSv4.0 LOCK replay cache
CVE-2026-23450 9.8 CRITICAL net/smc: fix NULL dereference and UAF in smc_tcp_syn_recv_sock()
CVE-2026-23428 9.8 CRITICAL ksmbd: fix use-after-free of share_conf in compound request
CVE-2026-23455 9.1 CRITICAL netfilter: nf_conntrack_h323: check for zero length in DecodeQ931()
CVE-2026-23425 8.8 HIGH KVM: arm64: Fix ID register initialization for non-protected pKVM guests
CVE-2026-23461 8.8 HIGH Bluetooth: L2CAP: Fix use-after-free in l2cap_unregister_user
CVE-2026-23462 8.8 HIGH Bluetooth: HIDP: Fix possible UAF
CVE-2026-23457 8.6 HIGH netfilter: nf_conntrack_sip: fix Content-Length u32 truncation in sip_help_tcp()
CVE-2026-23459 8.2 HIGH ip_tunnel: adapt iptunnel_xmit_stats() to NETDEV_PCPU_STAT_DSTATS
CVE-2026-23456 8.2 HIGH netfilter: nf_conntrack_h323: fix OOB read in decode_int() CONS case
CVE-2026-31393 8.1 HIGH Bluetooth: L2CAP: Validate L2CAP_INFO_RSP payload length before access
CVE-2026-31392 8.1 HIGH smb: client: fix krb5 mount with username option
CVE-2026-31396 7.8 HIGH net: macb: fix use-after-free access to PTP clock
CVE-2026-23466 7.8 HIGH drm/xe: Open-code GGTT MMIO access protection
CVE-2026-31401 7.8 HIGH HID: bpf: prevent buffer overflow in hid_hw_request
CVE-2026-23437 7.8 HIGH net: shaper: protect late read accesses to the hierarchy
CVE-2026-23458 7.8 HIGH netfilter: ctnetlink: fix use-after-free in ctnetlink_dump_exp_ct()
CVE-2026-23444 7.8 HIGH wifi: mac80211: always free skb on ieee80211_tx_prepare_skb() failure
CVE-2026-23445 7.8 HIGH igc: fix page fault in XDP TX timestamps handling
CVE-2026-23449 7.8 HIGH net/sched: teql: Fix double-free in teql_master_xmit

Showing top 20 of 71 CVEs. View all on vendor page &rarr; →

IV. Related Vulnerabilities

Same product: Linux
Same vendor: Linux

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