CVE-2025-21844 smb: client: Add check for next_buffer in receive_encrypted_standard()

What is CVE-2025-21844?

CVE-2025-21844 is a high-severity vulnerability in Linux kernel, published on 12 Mar 2025. An attacker can exploit it over the internet without logging in, with no action from the victim.

Official description

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

smb: client: Add check for next_buffer in receive_encrypted_standard()

Add check for the return value of cifs_buf_get() and cifs_small_buf_get() in receive_encrypted_standard() to prevent null pointer dereference.

Weakness: CWE-476

Which versions are affected by CVE-2025-21844?

It affects 1 product.

Products include Linux kernel.

How do I fix CVE-2025-21844?

Apply the vendor's patch.

Is CVE-2025-21844 being exploited?

There is no known exploitation of CVE-2025-21844 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-58518, BELL-CVE-2025-21844, DEBIAN-CVE-2025-21844, GHSA-45ff-v9gq-xww8, ROOT-OS-UBUNTU-2404-CVE-2025-21844, UBUNTU-CVE-2025-21844.