SB2026091290 - NULL pointer dereference in Linux kernel nfsd

Description

This security bulletin contains information about 1 vulnerability.

1) NULL pointer dereference (CVE-ID: CVE-2026-89696)

CWE-ID: CWE-476 - NULL Pointer Dereference

CVSSv4: 8.2 [CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N]

The vulnerability allows a remote attacker to cause a denial of service.

The vulnerability exists due to a null pointer dereference in the NFS server compound request dispatch loop when processing a crafted NFSv4 COMPOUND request involving an inter-SSC COPY operation. A remote attacker can send a crafted NFSv4 COMPOUND request with an operation between a foreign PUTFH and SAVEFH to cause a denial of service.

Only systems with CONFIG_NFSD_V4_2_INTER_SSC enabled are affected.

Remediation

Install update from vendor's website.

References

• https://git.kernel.org/stable/c/311f7d926630940650447cbd1c932b076b40a6c4
• https://git.kernel.org/stable/c/35f248bd40b47b229d4999581df45b97daadd977
• https://git.kernel.org/stable/c/bf4d338dc8625d70c7f2cb0657d66851a7ac9154
• https://git.kernel.org/stable/c/c59738a00aa51b16adc1b5ceb7c80877168efb4d