SB2026091289 - Inefficient Algorithmic Complexity in Linux kernel nfsd

Description

This security bulletin contains information about 1 vulnerability.

1) Inefficient Algorithmic Complexity (CVE-ID: CVE-2026-89695)

CWE-ID: CWE-407 - Inefficient Algorithmic Complexity

CVSSv4: 8.7 [CVSS:4.0/AV:N/AC:L/AT:N/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 inefficient algorithmic complexity in nfsd4_decode_posixacl() when processing an NFSv4 POSIX ACL with a user-controlled entry count. A remote attacker can submit an ACL with a large entry count to cause a denial of service.

The entry count is used by a quadratic bubble sort during NFS server compound request processing.

Remediation

Install update from vendor's website.

References

• https://git.kernel.org/stable/c/4bc1108e876153a2dd6d874052b99182c3603135
• https://git.kernel.org/stable/c/ea14d71d6ecb925673761bcf79f781f7dc9042cc