SB2026072148 - Memory leak in Linux kernel nfsd

Description

This security bulletin contains information about 1 vulnerability.

1) Memory leak (CVE-ID: CVE-2026-53395)

CWE-ID: CWE-401 - Missing release of memory after effective lifetime

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 a memory leak in nfsd4_create in the NFS server when processing a CREATE request with both FATTR4_WORD0_ACL and FATTR4_WORD2_POSIX_DEFAULT_ACL or FATTR4_WORD2_POSIX_ACCESS_ACL encoded in the same fattr bitmap. A remote attacker can send repeated specially crafted CREATE requests to cause a denial of service.

The issue leaks two posix_acl slab objects per request, which can lead to unbounded slab exhaustion.

Remediation

Install update from vendor's website.

References

• https://git.kernel.org/stable/c/8371cc5c0a2cc2a71b3dcfd47ff1f7fcfc526a5e
• https://git.kernel.org/stable/c/a60f25a800846ab8e5a13f8a9d05111f2aee55a7