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CVE-2026-64387: smb: client: fix query directory replay double-free

• Severity: critical (CVSS 9.8 v3.1)
• Exploited in the wild: not listed in CISA KEV
• EPSS: 0.5% probability of exploitation in the next 30 days
• Public exploit or detection template: none known
• Published: 2026-07-25 · updated 2026-10-19
• Weakness: CWE-415

Description

In the Linux kernel, the following vulnerability has been resolved: smb: client: fix query directory replay double-free A response-bearing attempt can return a replayable error and free its response buffer. If SMB2_query_directory_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.

Affected products

• Linux kernel: from 6.6.32 before 6.6.145; from 6.8.1 before 6.12.96; from 6.13 before 6.18.39; from 6.19 before 7.1.4; 6.8, 6.8-rc2, 6.8-rc3, 6.8-rc4, 6.8-rc5, 6.8-rc6 (+1) — fixed in 6.12.96, 6.18.39, 6.6.145, 7.1.4

How to fix

Upgrade to a fixed version: Linux kernel 6.12.96, 6.18.39, 6.6.145, 7.1.4. Check the vendor advisory for mitigations.

References

• https://git.kernel.org/stable/c/00b0fa425941438b664950a8ee65dfba2def4336
• https://git.kernel.org/stable/c/1665f25b1dea30bf2d02e16245d203a944c9d994
• https://git.kernel.org/stable/c/3317a5d015fca976475aa71df224056777316fde
• https://git.kernel.org/stable/c/3409aedf3c81a810243da94164f6621c9d205c98
• https://git.kernel.org/stable/c/9647492b5e41954be59d5157eddbcd4cdc1656f7

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