CVE-2026-64381 smb: client: Fix next buffer leak in receive_encrypted_standard()

What is CVE-2026-64381?

CVE-2026-64381 is a high-severity memory corruption vulnerability in Linux kernel, published on 25 Jul 2026. It can only be exploited from the same machine or local network, with no action from the victim.

Official description

In the Linux kernel, the following vulnerability has been resolved:

smb: client: Fix next buffer leak in receive_encrypted_standard()

receive_encrypted_standard() allocates next_buffer before checking whether the number of compound PDUs already reached MAX_COMPOUND. If the limit check fails, the function returns immediately and the newly allocated next_buffer is not assigned to server->smallbuf/server->bigbuf, making it leaked.

Move the MAX_COMPOUND check before allocating next_buffer.

Weakness: CWE-787

Which versions are affected by CVE-2026-64381?

It affects 1 product.

Products include Linux kernel.

How do I fix CVE-2026-64381?

Apply the vendor's patch.

Upgrade to the fixed version. Memory-safe languages, compiler hardening and fuzzing prevent most new cases. More about Memory corruption.

Is CVE-2026-64381 being exploited?

There is no known exploitation of CVE-2026-64381 in the wild and no public exploit code.

Other vulnerabilities in Linux kernel

• CVE-2026-53266 Linux Kernel Out-of-Bounds Write Exploited High 8.8
• CVE-2013-6282 Linux Kernel Improper Input Validation Exploited High 8.8
• CVE-2022-0185 Linux Kernel Heap-Based Buffer Overflow Exploited High 8.4
• CVE-2013-2094 Linux Kernel Privilege Escalation Exploited High 8.4
• CVE-2026-53362 Linux Kernel Unspecified Exploited High 7.8

All Linux kernel vulnerabilities

Sources

• CVE record
• NVD
• OSV
• GitHub advisory
• How this page is made

Also known as AZL-93437, BELL-CVE-2026-64381, DEBIAN-CVE-2026-64381, GHSA-v5fg-wc2f-7h9h, ROOT-OS-UBUNTU-2204-CVE-2026-64381, UBUNTU-CVE-2026-64381.