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

Affected: Linux

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_rep…

USN-8490-1 — linux, linux-aws, linux-aws-6.17, linux-gcp, linux-gcp-6.17, linux-oracle, linux-oracle-6.17 vulnerabilities

Affected: Ubuntu:24.04:LTS: linux-aws-6.17, Ubuntu:24.04:LTS: linux-gcp-6.17, Ubuntu:24.04:LTS: linux-oracle-6.17, Ubuntu:25.10: linux, Ubuntu:25.10: linux-aws, Ubuntu:25.10: linux-gcp, Ubuntu:25.10: linux-oracle

Several security issues were discovered in the Linux kernel. An attacker could possibly use these to compromise the system. This update corrects flaws in the following subsystems: - ARM64 architecture; - Block layer subsystem; - Cryptographic API; - DMA engine subsystem; - InfiniBand drivers; - STMicroelectronics network drivers; - Network drivers; - NVME drivers; - SCSI subsystem; - USB over IP driver; - File systems infrastructure; - Ext4 file system; - Network file system (NFS) server daemon; - SMB network file system; - Kernel thread helper (kthread); - IPv6 networking; - Tracing infrastructure; - Kernel exit() syscall; - Scatterlist API; - B.A.T.M.A.N. meshing protocol; - Ethernet bridge; - Ceph Core library; - IPv4 networking; - Multipath TCP; - Netfilter; - RxRPC session sockets; - SMC sockets; - X.25 network layer; (CVE-2026-22984, CVE-2026-23272, CVE-2026-23278, CVE-2026-23392, CVE-2026-23427, CVE-2026-23428, CVE-2026-23450, CVE-2026-23455, CVE-2026-31402, CVE-2026-31418, CVE-2026-31436, CVE-2026-31448, CVE-2026-31478, CVE-2026-31607, CVE-2026-31635, CVE-2026-31637, CVE-2026-31649, CVE-2026-31657, CVE-2026-31659, CVE-2026-31668, CVE-2026-31669, CVE-2026-31682, CVE-2026-31685, CVE-2026-31718, CVE-2026-43011, CVE-2026-43037, CVE-2026-43038, CVE-2026-43071, CVE-2026-43083, CVE-2026-43114, CVE-2026-43117, CVE-2026-43125, CVE-2026-43186, CVE-2026-43197, CVE-2026-43304, CVE-2026-43341, CVE-2026-43376, CVE-2026-43378,…

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

USN-8490-1 — linux, linux-aws, linux-aws-6.17, linux-gcp, linux-gcp-6.17, linux-oracle, linux-oracle-6.17 vulnerabilities