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CVE-2026-64390— ksmbd: track the connection owning a byte-range lock

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基金会开源的一款操作系统内核。 Linux kernel 5.15版本存在安全漏洞，该漏洞源于ksmbd在管理字节范围锁时未正确跟踪连接所有权，可能导致释放后重用。

CVSS 8.8 · High EPSS 0.47% · P39

Possible ATT&CK Techniques 1 AI

T1211 · Exploitation for Stealth

Affected Version Matrix 16

VendorProduct Version RangeStatus
Linux Linux f5a544e3bab78142207e0242d22442db85ba1eff< 22d38cf75b556c20b039743bdf3654d535b858be affected
f5a544e3bab78142207e0242d22442db85ba1eff< 66eb3643164e5e1029907793926c132f8b5c6148 affected
f5a544e3bab78142207e0242d22442db85ba1eff< ea5c9bf99f626a15cc59f645dc895f2b3f01992e affected
f5a544e3bab78142207e0242d22442db85ba1eff< fe20d492a69a6f79e637f438072b212e21ed3b78 affected
f5a544e3bab78142207e0242d22442db85ba1eff< 427faaa52b0b399940c1a88065a5c310d10dad15 affected
f5a544e3bab78142207e0242d22442db85ba1eff< 5fecc15a30cb9ebd310f7b52c1ab607edcea78f6 affected
f5a544e3bab78142207e0242d22442db85ba1eff< c1016dd1d8b2bcd1158bbaabe94a31bb7e7431fb affected
5.15 affected
… +8 more rows
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I. Basic Information for CVE-2026-64390

Vulnerability Information
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Vulnerability Title
ksmbd: track the connection owning a byte-range lock
Source: CVE Program / CVE List V5
Vulnerability Description
In the Linux kernel, the following vulnerability has been resolved: ksmbd: track the connection owning a byte-range lock SMB2_LOCK adds each granted byte-range lock to both the file lock list and the lock list of the connection which handled the request. The final close and durable handle paths, however, remove the connection list entry while holding fp->conn->llist_lock. With SMB3 multichannel, the connection handling the LOCK request can be different from the connection which opened the file. The entry can therefore be removed under a different spinlock from the one protecting the list it belongs to. A concurrent traversal can then access freed struct ksmbd_lock and struct file_lock objects. Record the connection owning each lock's clist entry and hold a reference to it while the entry is linked. Use that connection and its llist_lock for unlock, rollback, close, and durable preserve. Durable reconnect assigns the new connection as the owner when publishing the locks again.
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基金会开源的一款操作系统内核。 Linux kernel 5.15版本存在安全漏洞，该漏洞源于ksmbd在管理字节范围锁时未正确跟踪连接所有权，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)

Affected Products

Vendor Product Affected Versions CPE Subscribe
Linux Linux f5a544e3bab78142207e0242d22442db85ba1eff ~ 22d38cf75b556c20b039743bdf3654d535b858be -
Linux Linux 5.15 -

II. Public POCs for CVE-2026-64390

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III. Intelligence Information for CVE-2026-64390

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Patches & Fixes for CVE-2026-64390 (5)

Same Patch Batch · Linux · 2026-07-25 · 274 CVEs total

CVE-2026-64355 9.8 CRITICAL bpf: Reject fragmented frames in devmap
CVE-2026-64410 9.8 CRITICAL netfilter: flowtable: IPIP tunnel hardware offload is not yet support
CVE-2026-64399 9.8 CRITICAL ksmbd: add permission checks for FSCTL_DUPLICATE_EXTENTS_TO_FILE
CVE-2026-64397 9.8 CRITICAL ksmbd: serialize QUERY_DIRECTORY requests per file
CVE-2026-64391 9.8 CRITICAL ksmbd: use opener credentials for ADS I/O
CVE-2026-64387 9.8 CRITICAL smb: client: fix query directory replay double-free
CVE-2026-64386 9.8 CRITICAL smb: client: fix query_info() replay double-free
CVE-2026-64385 9.8 CRITICAL smb: client: fix double-free in SMB2_ioctl() replay
CVE-2026-64383 9.8 CRITICAL smb: client: fix double-free in SMB2_flush() replay
CVE-2026-64384 9.8 CRITICAL smb: client: fix change notify replay double-free
CVE-2026-64268 9.8 CRITICAL RDMA/siw: bound Read Response placement to the RREAD length
CVE-2026-64439 9.8 CRITICAL crypto: krb5 - filter out async aead implementations at alloc
CVE-2026-64303 9.8 CRITICAL spi: fsl-lpspi: terminate the RX channel on TX prepare failure path
CVE-2026-64523 9.8 CRITICAL net/handshake: Take a long-lived file reference at submit
CVE-2026-64459 9.8 CRITICAL tcp: restore RCU grace period in tcp_ao_destroy_sock
CVE-2026-64393 9.1 CRITICAL ksmbd: run set info with opener credentials
CVE-2026-64392 9.1 CRITICAL ksmbd: use opener credentials for delete-on-close
CVE-2026-64269 9.1 CRITICAL RDMA/rtrs-srv: Bound RDMA-Write length to chunk size in rdma_write_sg
CVE-2026-64319 9.1 CRITICAL nvmet-auth: validate reply message payload bounds against transfer length
CVE-2026-64257 9.1 CRITICAL smb: client: reject overlapping data areas in SMB2 responses

Showing top 20 of 274 CVEs. View all on vendor page &rarr; →

IV. Related Vulnerabilities

Same product: Linux
Same vendor: Linux

V. Comments for CVE-2026-64390

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