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CVE-2026-74521— ksmbd: use memcmp() to compare ClientGUIDs

CVSS 9.1 · Critical EPSS 0.32% · P24

Possible ATT&CK Techniques 1AI

T1190 · Exploit Public-Facing Application

Affected Version Matrix 6

VendorProductVersion RangeStatus
LinuxLinuxe2f34481b24db2fd634b5edb0a5bd0e4d38cc6e9< d535363299822c5caa543787b21bd5cfa3e41949affected
e2f34481b24db2fd634b5edb0a5bd0e4d38cc6e9< e8bb506e6ef749ac0336f3e579d8d02396b7d832affected
5.15affected
< 5.15unaffected
7.1.8≤ 7.1.*unaffected
7.2≤ *unaffected
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I. Basic Information for CVE-2026-74521

Vulnerability Information
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Vulnerability Title
ksmbd: use memcmp() to compare ClientGUIDs
Source: CVE Program / CVE List V5
Vulnerability Description
In the Linux kernel, the following vulnerability has been resolved: ksmbd: use memcmp() to compare ClientGUIDs ClientGUID is a fixed-size binary value and can contain embedded NUL bytes. strncmp() stops comparing at the first NUL byte, so different ClientGUID values can incorrectly be treated as equal. Use memcmp() in SMB3 multichannel session binding and FSCTL_VALIDATE_NEGOTIATE_INFO to compare all SMB2_CLIENT_GUID_SIZE bytes.
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:N
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基金会开源的一个操作系统内核。 Linux kernel 5.15版本存在安全漏洞，该漏洞源于ksmbd使用strncmp()比较ClientGUID时，由于ClientGUID为固定大小的二进制值且可能包含嵌入的NUL字节，strncmp()会在第一个NUL字节处停止比较，导致不同的ClientGUID值可能被错误地视为相等。
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

VendorProductAffected VersionsCPESubscribe
LinuxLinux e2f34481b24db2fd634b5edb0a5bd0e4d38cc6e9 ~ d535363299822c5caa543787b21bd5cfa3e41949 -
LinuxLinux 5.15 -

II. Public POCs for CVE-2026-74521

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III. Intelligence Information for CVE-2026-74521

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Patches & Fixes for CVE-2026-74521 (2)

Same Patch Batch · Linux · 2026-08-15 · 845 CVEs total

CVE-2026-7428010.0 CRITICALcrypto: marvell/octeontx - fix DMA cleanup using wrong loop index
CVE-2026-7447510.0 CRITICALvxlan: use neigh_ha_snapshot() in route_shortcircuit()
CVE-2026-7240710.0 CRITICALgeneve: validate inner network offset in geneve_gro_complete()
CVE-2026-7430910.0 CRITICALvdpa/octeon_ep: fix IRQ-to-ring mapping in interrupt handler
CVE-2026-7240810.0 CRITICALgeneve: gate GRO hint in geneve_gro_complete() on gs->gro_hint
CVE-2026-7242110.0 CRITICALipv4: fib: Don't ignore error route in local/main tables.
CVE-2026-7427910.0 CRITICALcrypto: cavium/cpt - fix DMA cleanup using wrong loop index
CVE-2026-724939.9 CRITICALnet: serialize netif_running() check in enqueue_to_backlog()
CVE-2026-720849.8 CRITICALscsi: target: Bound PR-OUT TransportID parsing to the received buffer
CVE-2026-722499.8 CRITICALnetfilter: flowtable: use dst in this direction when pushing IPIP header
CVE-2026-722489.8 CRITICALnetfilter: flowtable: support IPIP tunnel with direct xmit
CVE-2026-722209.8 CRITICALsunrpc: harden rq_procinfo lifecycle to prevent double-free
CVE-2026-724949.8 CRITICALRDMA/irdma: Replace waitqueue and flag with completion
CVE-2026-743459.8 CRITICALRDMA/siw: Fix endpoint/socket association handling
CVE-2026-742559.8 CRITICALtipc: fix UAF in tipc_l2_send_msg()
CVE-2026-722219.8 CRITICALsunrpc: wait for in-flight TLS handshake callback when cancel loses race
CVE-2026-722269.8 CRITICALbatman-adv: tt: prevent TVLV OOB check overflow
CVE-2026-744289.8 CRITICALrxrpc: Fix double unlock in rxrpc_recvmsg()
CVE-2026-720839.8 CRITICALscsi: target: core: Fix iSCSI ISID use-after-free in REGISTER AND MOVE
CVE-2026-722349.8 CRITICALbatman-adv: access unicast_ttvn skb->data only after skb realloc

Showing top 20 of 845 CVEs. View all on vendor page &rarr; →

IV. Related Vulnerabilities

Same product: Linux
Same vendor: Linux

V. Comments for CVE-2026-74521

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