CVE-2026-72381 — ksmbd: fix use-after-free of fp->owner.name in durable handle owner check

Affected: Linux

In the Linux kernel, the following vulnerability has been resolved:

ksmbd: fix use-after-free of fp->owner.name in durable handle owner check

Two concurrent SMB2 durable reconnects (DH2C/DHnC) on the same persistent_id race the fp->owner.name compare-read in ksmbd_vfs_compare_durable_owner() against the kfree() in ksmbd_reopen_durable_fd()'s reopen-success path. fp->owner.name is a standalone kstrdup() buffer whose lifetime is independent of the fp refcount, and the two sites share no lock: the compare reads the buffer while the reopen frees it, so the strcmp() can dereference freed memory.

Commit 7ce4fc40018d ("ksmbd: fix durable reconnect double-bind race in ksmbd_reopen_durable_fd") made the fp->conn claim atomic under global_ft.lock (closing the owner.name double-free and the ksmbd_file write-UAF), but the compare-read versus reopen-free pair was left unserialized.

BUG: KASAN: slab-use-after-free in strcmp+0x2c/0x80 Read of size 1 by task kworker strcmp ksmbd_vfs_compare_durable_owner smb2_check_durable_oplock smb2_open Freed by task kworker: kfree ksmbd_reopen_durable_fd smb2_open Allocated by task kworker: kstrdup session_fd_check smb2_session_logoff The buggy address belongs to the cache kmalloc-8

Serialize both sides of the race with fp->f_lock. The global durable file-table lock still protects the durable reconnect claim, but fp->owner.name is per-open state and does not need to block unrelated durable table lo…

USN-8816-1 — linux, linux-aws, linux-aws-7.0, linux-hwe-7.0, linux-ibm, linux-oracle, linux-raspi, linux-realtime vulnerabilities

Affected: Ubuntu:24.04:LTS: linux-aws-7.0, Ubuntu:24.04:LTS: linux-hwe-7.0, Ubuntu:26.04:LTS: linux, Ubuntu:26.04:LTS: linux-aws, Ubuntu:26.04:LTS: linux-ibm, Ubuntu:26.04:LTS: linux-oracle, Ubuntu:26.04:LTS: linux-raspi, Ubuntu:26.04:LTS: linux-realtime

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; - S390 architecture; - x86 architecture; - DRBD Distributed Replicated Block Device drivers; - InfiniBand drivers; - IOMMU subsystem; - Multiple devices driver; - Network drivers; - Microsoft Azure Network Adapter (MANA) driver; - NVME drivers; - TCM subsystem; - Virtio Host (VHOST) subsystem; - Xen hypervisor drivers; - AFS file system; - File systems infrastructure; - Network file systems library; - Network file system (NFS) client; - NTFS3 file system; - OCFS2 file system; - OrangeFS file system; - SMB network file system; - IPv4 networking; - Sun RPC protocol; - IPv6 networking; - IP tunnels definitions; - Netfilter; - TCP network protocol; - Locking primitives; - 9P file system network protocol; - B.A.T.M.A.N. meshing protocol; - Networking core; - IFE protocol; - RxRPC session sockets; - Network traffic control; - SCTP protocol; - SMC sockets; - TIPC protocol; - XFRM subsystem; (CVE-2026-64530, CVE-2026-64534, CVE-2026-64535, CVE-2026-64541, CVE-2026-64551, CVE-2026-68083, CVE-2026-68457, CVE-2026-68476, CVE-2026-68477, CVE-2026-72014, CVE-2026-72020, CVE-2026-72033, CVE-2026-72041, CVE-2026-72046, CVE-2026-72064, CVE-2026-72065, CVE-2026-72069, CVE-2026-72083, CVE-2026-72084, CVE-2026-72085, CVE…

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CVE-2026-72381 — ksmbd: fix use-after-free of fp->owner.name in durable handle owner check

USN-8816-1 — linux, linux-aws, linux-aws-7.0, linux-hwe-7.0, linux-ibm, linux-oracle, linux-raspi, linux-realtime vulnerabilities