OCTOBER 12, 2026
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Case File

CVE-2026-90149

HIGH · CVSS 7.5 EPSS 0.61%

Source: NVD + CISA KEV + EPSS · Published 2026-09-17 · Last synced 2026-10-12

CyberRota Analysis

AI-Generated

The vulnerability affects the Linux kernel's handling of NFSv4.0 data servers, where incorrect assumptions about session management can lead to NULL dereferences during I/O operations. This can result in system crashes or instability, particularly impacting environments relying on NFSv4.0 for file sharing. Administrators of systems utilizing NFSv4.0 should prioritize applying the relevant patches to mitigate potential disruptions.

CVE
CVE-2026-90149
Severity
HIGH
CVSS
7.5
EPSS
0.61%
Linux

Original NVD Description

In the Linux kernel, the following vulnerability has been resolved: NFSv4/flexfiles: fix NULL dereference for NFSv4.0 data servers flexfiles accepts NFSv4.0 data servers, but two NFSv4 code paths assume the data server client has a session. Unlike NFSv4.1+, an NFSv4.0 client has no session (clp->cl_session is NULL; it uses clp->cl_slot_tbl), so I/O to a v4.0 flexfiles DS oopses: - nfs4_init_ds_session() dereferences clp->cl_session->session_state while seeding the DS lease. It also only seeds cl_lease_time when NFS4_SESSION_INITING is set; without a session that never happens, so cl_lease_time stays 0 and nfs4_renew_state() busy-loops, requeuing every 5 seconds. Seed the lease whenever there is no session and return before touching session state. - ff_layout_async_handle_error_v4() dereferences clp->cl_session->fc_slot_table on every DS I/O error. Fall back to the v4.0 transport slot table (clp->cl_slot_tbl) when there is no session.