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CVE-2026-64386— smb: client: fix query_info() replay double-free

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存在安全漏洞，该漏洞源于smb客户端的query_info函数在处理响应缓冲区时存在双重释放问题。

CVSS 9.8 · Critical EPSS 0.46% · P38

Possible ATT&CK Techniques 1 AI

T1211 · Exploitation for Stealth

Affected Version Matrix 13

VendorProduct Version RangeStatus
Linux Linux 433042a91f9373241307725b52de573933ffedbf< 100fb7c455fa86d248b8bd7bb9de757c192870b4 affected
4f1fffa2376922f3d1d506e49c0fd445b023a28e< 3c81dda84799f76b42aec598564316e2964440db affected
4f1fffa2376922f3d1d506e49c0fd445b023a28e< f1add4acb656f5a82806a1ab0e63fed3d8b1bfca affected
4f1fffa2376922f3d1d506e49c0fd445b023a28e< 89234773e8348918111aa15f6922b58cf3843364 affected
4f1fffa2376922f3d1d506e49c0fd445b023a28e< 2a88561d66eb855813cf004a0abe648bbb17de5e affected
6.6.32< 6.6.145 affected
6.8 affected
< 6.8 unaffected
… +5 more rows
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I. Basic Information for CVE-2026-64386

Vulnerability Information
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Vulnerability Title
smb: client: fix query_info() replay double-free
Source: CVE Program / CVE List V5
Vulnerability Description
In the Linux kernel, the following vulnerability has been resolved: smb: client: fix query_info() replay double-free A response-bearing attempt can return a replayable error and free its response buffer. If SMB2_query_info_init() fails before the next send, cleanup retains the previous buffer type and frees that response again. Reset response bookkeeping before each attempt to prevent the stale free.
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存在安全漏洞，该漏洞源于smb客户端的query_info函数在处理响应缓冲区时存在双重释放问题。
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 433042a91f9373241307725b52de573933ffedbf ~ 100fb7c455fa86d248b8bd7bb9de757c192870b4 -
Linux Linux 6.8 -

II. Public POCs for CVE-2026-64386

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III. Intelligence Information for CVE-2026-64386

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Patches & Fixes for CVE-2026-64386 (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-2026-64385 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-2026-64319 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
CVE-2026-64269 9.1 CRITICAL RDMA/rtrs-srv: Bound RDMA-Write length to chunk size in rdma_write_sg
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-2026-64320 9.1 CRITICAL nvmet: fix pre-auth out-of-bounds heap read in Discovery Get Log Page

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-2026-64386

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