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CVE-2026-53198— ksmbd: fix use-after-free of a deferred file_lock on double SMB2_CANCEL

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基金会开源的操作系统Linux所使用的内核。 Linux kernel存在安全漏洞，该漏洞源于ksmbd在双重SMB2_CANCEL操作中对延迟文件锁的释放后重用，可能导致经过身份验证的SMB客户端利用释放后重用。

CVSS 8.8 · High EPSS 0.45% · P37

Possible ATT&CK Techniques 1 AI

T1190 · Exploit Public-Facing Application

Affected Version Matrix 14

VendorProduct Version RangeStatus
Linux Linux e2f34481b24db2fd634b5edb0a5bd0e4d38cc6e9< b7063c7426ea5a4d15e01b60538718765392f49d affected
e2f34481b24db2fd634b5edb0a5bd0e4d38cc6e9< 0da2e073f9cbf4985a0fd9acb71bc5ff599f8afd affected
e2f34481b24db2fd634b5edb0a5bd0e4d38cc6e9< 89ae9df09d2c1fb4a4eb495c113a7ce1dca34147 affected
e2f34481b24db2fd634b5edb0a5bd0e4d38cc6e9< 14d2eee0193ac3cd1bf3d014373449f0b8d35d6d affected
e2f34481b24db2fd634b5edb0a5bd0e4d38cc6e9< 2b2eda2821cff1d1b5a423b6ee7d8fc6fbc8e694 affected
e2f34481b24db2fd634b5edb0a5bd0e4d38cc6e9< f580d27e8928828693df44ba2db0fffdbe11dfea affected
5.15 affected
< 5.15 unaffected
… +6 more rows
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I. Basic Information for CVE-2026-53198

Vulnerability Information
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Vulnerability Title
ksmbd: fix use-after-free of a deferred file_lock on double SMB2_CANCEL
Source: CVE Program / CVE List V5
Vulnerability Description
In the Linux kernel, the following vulnerability has been resolved: ksmbd: fix use-after-free of a deferred file_lock on double SMB2_CANCEL A deferred byte-range lock (an SMB2_LOCK that blocks) registers an async work on conn->async_requests via setup_async_work(), with cancel_fn = smb2_remove_blocked_lock and cancel_argv[0] pointing at the struct file_lock. When the request is cancelled, the worker frees the file_lock with locks_free_lock() and takes the cancelled early-exit, which "goto out"s and never reaches release_async_work() -- the only site that unlinks the work from conn->async_requests and clears cancel_fn/cancel_argv. The work therefore stays matchable on async_requests with a live cancel_fn pointing at the freed file_lock, until connection teardown finally runs release_async_work(). smb2_cancel() fires cancel_fn unconditionally with no state guard, so a second SMB2_CANCEL for the same AsyncId, arriving in that window, re-runs smb2_remove_blocked_lock() on the freed file_lock -- a slab use-after-free: BUG: KASAN: slab-use-after-free in __locks_delete_block __locks_delete_block locks_delete_block ksmbd_vfs_posix_lock_unblock smb2_remove_blocked_lock smb2_cancel <- 2nd SMB2_CANCEL fires cancel_fn handle_ksmbd_work Allocated by ...: locks_alloc_lock <- smb2_lock Freed by ...: locks_free_lock <- smb2_lock (cancelled branch) ... cache file_lock_cache of size 192 Reproduced on mainline with KASAN by an authenticated SMB client. Skip a work whose state is already KSMBD_WORK_CANCELLED so its cancel callback cannot be fired a second time.
Source: CVE Program / CVE List V5
CVSS Information
CVSS:3.1/AV:N/AC:L/PR:L/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基金会开源的操作系统Linux所使用的内核。 Linux kernel存在安全漏洞，该漏洞源于ksmbd在双重SMB2_CANCEL操作中对延迟文件锁的释放后重用，可能导致经过身份验证的SMB客户端利用释放后重用。
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)

Affected Products

Vendor Product Affected Versions CPE Subscribe
Linux Linux e2f34481b24db2fd634b5edb0a5bd0e4d38cc6e9 ~ b7063c7426ea5a4d15e01b60538718765392f49d -
Linux Linux 5.15 -

II. Public POCs for CVE-2026-53198

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III. Intelligence Information for CVE-2026-53198

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Patches & Fixes for CVE-2026-53198 (6)

Same Patch Batch · Linux · 2026-06-25 · 146 CVEs total

CVE-2026-53176 9.8 CRITICAL IB/isert: Reject login PDUs shorter than ISER_HEADERS_LEN
CVE-2026-53247 9.8 CRITICAL net: ethernet: mtk_eth_soc: Fix use-after-free in metadata dst teardown
CVE-2026-53151 9.8 CRITICAL rxrpc: Fix the ACK parser to extract the SACK table for parsing
CVE-2026-53246 9.8 CRITICAL sctp: validate cached peer INIT chunk length in COOKIE_ECHO processing
CVE-2026-53260 9.8 CRITICAL tcp: Add preempt_{disable,enable}_nested() in reqsk_queue_hash_req().
CVE-2026-53175 9.8 CRITICAL inet: frags: fix use-after-free caused by the fqdir_pre_exit() flush
CVE-2026-53228 9.8 CRITICAL ipv6: sit: reload inner IPv6 header after GSO offloads
CVE-2026-53215 9.8 CRITICAL net: mvpp2: refill RX buffers before XDP or skb use
CVE-2026-53216 9.8 CRITICAL net: mvpp2: limit XDP frame size to the RX buffer
CVE-2026-53221 9.8 CRITICAL ip6_vti: fix incorrect tunnel matching in vti6_tnl_lookup()
CVE-2026-53131 9.4 CRITICAL netfilter: require Ethernet MAC header before using eth_hdr()
CVE-2026-53225 9.1 CRITICAL sctp: fix uninit-value in __sctp_rcv_asconf_lookup()
CVE-2026-53186 9.1 CRITICAL RDMA/srp: bound SRP_RSP sense copy by the received length
CVE-2026-53224 9.1 CRITICAL sctp: validate embedded INIT chunk and address list lengths in cookie
CVE-2026-53159 8.8 HIGH misc: fastrpc: fix DMA address corruption due to find_vma misuse
CVE-2026-53188 8.8 HIGH RDMA/core: Validate the passed in fops for ib_get_ucaps()
CVE-2026-53248 8.8 HIGH net: airoha: Fix use-after-free in metadata dst teardown
CVE-2026-53200 8.8 HIGH KVM: arm64: nv: Fix handling of XN[0] when !FEAT_XNX
CVE-2026-53171 8.8 HIGH accel/ethosu: fix arithmetic issues in dma_length()
CVE-2026-53170 8.8 HIGH accel/ethosu: reject DMA commands with uninitialized length

Showing top 20 of 146 CVEs. View all on vendor page &rarr; →

IV. Related Vulnerabilities

Same product: Linux
Same vendor: Linux

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