Memory leak in Linux kernel - CVE-2026-53394

Vulnerability identifier: #VU138871

CSH Severity: Low

CVSS v4: 6.3 [CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:N/VC:N/VI:N/VA:L/SC:N/SI:N/SA:N]

CVE-ID: CVE-2026-53394

CWE-ID: CWE-401

Exploitation vector: Remote access

Exploit availability: No public exploit available

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

The vulnerability exists due to a memory leak in find_or_alloc_open_stateowner() in the NFSv4 server state handling code when processing concurrent NFSv4.0 OPEN operations with the same owner string during an unconfirmed retry race. A remote attacker can trigger repeated racing OPEN requests to cause a denial of service.

The issue requires a narrow but repeatable race condition involving two NFSv4.0 OPEN threads and a concurrent insertion of a new unconfirmed owner between retry iterations.

Linux kernel
Ubuntu
linux (Ubuntu package)
linux-azure (Ubuntu package)
linux-gcp-7.0 (Ubuntu package)
linux-oracle-7.0 (Ubuntu package)
linux-oem-7.0 (Ubuntu package)
linux-azure-7.0 (Ubuntu package)

Install security update from vendor's repository.

Linux kernel - update to 7.0 rc3
linux (Ubuntu package) - addressed in versions 7.0.0-31.31, 7.0.0-31.31.1, 7.0.0-31.31~24.04.1, 7.0.0-1006.7, 7.0.0-1011.11~24.04.1, 7.0.0-1012.12, 7.0.0-1012.12~24.04.1
linux-azure (Ubuntu package) - addressed in versions 7.0.0-1011.11, 7.0.0-1014.14
linux-gcp-7.0 (Ubuntu package) - update to 7.0.0-1011.11~24.04.1
linux-oracle-7.0 (Ubuntu package) - update to 7.0.0-1011.11~24.04.1
linux-oem-7.0 (Ubuntu package) - update to 7.0.0-1013.13
linux-azure-7.0 (Ubuntu package) - update to 7.0.0-1014.14~24.04.1

• https://git.kernel.org/stable/c/017a6150106b054cc84d1b0582d97bd3a74d4281
• https://git.kernel.org/stable/c/57aee7a35bb12753057c5b65d72d1f46c0e95b07
• https://git.kernel.org/stable/c/a10bf67fe06469a71a401f72f328237345d553c0
• https://git.kernel.org/stable/c/c9aefb2b5f11337c9202c5bd0c45d71198449718

• Memory leak in Linux kernel nfsd
• Ubuntu update for linux-oem-7.0
• Ubuntu update for linux
• Ubuntu update for linux-gcp-7.0
• Ubuntu update for linux-oracle-7.0
• Ubuntu update for linux-azure
• Ubuntu update for linux-azure-7.0