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CVE-2026-64397— ksmbd: serialize QUERY_DIRECTORY requests per file

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，该漏洞源于并发QUERY_DIRECTORY请求中指针覆盖导致栈释放后重用。

CVSS 9.8 · Critical EPSS 0.48% · P40

Possible ATT&CK Techniques 1 AI

T1190 · Exploit Public-Facing Application

Affected Version Matrix 14

VendorProduct Version RangeStatus
Linux Linux e2f34481b24db2fd634b5edb0a5bd0e4d38cc6e9< 1426fd79102539bc0ab5c8fced047ad4313b9908 affected
e2f34481b24db2fd634b5edb0a5bd0e4d38cc6e9< 2a64dbf9c739ddf7a25a066507597bf89f8f73d2 affected
e2f34481b24db2fd634b5edb0a5bd0e4d38cc6e9< 64dac2d486ec1eb18dc00968b16a230b6b75ec24 affected
e2f34481b24db2fd634b5edb0a5bd0e4d38cc6e9< a1d5d31cad593ea5e1b637f2f39c9ef6d09d1199 affected
e2f34481b24db2fd634b5edb0a5bd0e4d38cc6e9< fd22b039a5a05bc1d6818e9dcd1001fb432a829d affected
e2f34481b24db2fd634b5edb0a5bd0e4d38cc6e9< be6d26bf27499977c746abc163659915082348d8 affected
5.15 affected
< 5.15 unaffected
… +6 more rows
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I. Basic Information for CVE-2026-64397

Vulnerability Information
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Vulnerability Title
ksmbd: serialize QUERY_DIRECTORY requests per file
Source: CVE Program / CVE List V5
Vulnerability Description
In the Linux kernel, the following vulnerability has been resolved: ksmbd: serialize QUERY_DIRECTORY requests per file smb2_query_dir() stores a pointer to its stack-allocated private data in the ksmbd_file readdir_data. Concurrent QUERY_DIRECTORY requests using the same file handle can overwrite this pointer while an iterate_dir() callback is still using it, resulting in a stack use-after-free. Add a per-file mutex and hold it while accessing the shared directory enumeration state. The lock covers scan restart, dot entry state, readdir_data setup and iteration, and response construction. This prevents another request from replacing readdir_data.private before the current request has finished using it and also serializes the shared file position.
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，该漏洞源于并发QUERY_DIRECTORY请求中指针覆盖导致栈释放后重用。
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 ~ 1426fd79102539bc0ab5c8fced047ad4313b9908 -
Linux Linux 5.15 -

II. Public POCs for CVE-2026-64397

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III. Intelligence Information for CVE-2026-64397

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Patches & Fixes for CVE-2026-64397 (6)

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-2026-64391 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-2026-64459 9.8 CRITICAL tcp: restore RCU grace period in tcp_ao_destroy_sock
CVE-2026-64523 9.8 CRITICAL net/handshake: Take a long-lived file reference at submit
CVE-2026-64392 9.1 CRITICAL ksmbd: use opener credentials for delete-on-close
CVE-2026-64319 9.1 CRITICAL nvmet-auth: validate reply message payload bounds against transfer length
CVE-2026-64269 9.1 CRITICAL RDMA/rtrs-srv: Bound RDMA-Write length to chunk size in rdma_write_sg
CVE-2026-64450 9.1 CRITICAL tipc: fix out-of-bounds read in broadcast Gap ACK blocks
CVE-2026-64393 9.1 CRITICAL ksmbd: run set info with opener credentials
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-2026-64397

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