CVE-2026-90149

HIGHCVSS 7.5/10

Last modified

CVE-2026-90149 is a high-severity vulnerability rated 7.5/10 on the CVSS scale. 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.

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.

Metrics

Affected Software

Source: CNA advisory (CVE.org). NVD analysis pending.

VendorProductVersions
LinuxLinux>= a7878ca140084ec267ede48fce64d7e60f6d873e, < 163c16e01f53fc8eb8d0f3484ae6c382265ecbbd; >= a7878ca140084ec267ede48fce64d7e60f6d873e, < 436a214514e24103159aea455147d58b44a8a585; >= a7878ca140084ec267ede48fce64d7e60f6d873e, < 2b03ebbf8d5e8f6af4ecd6c65375232dd1ec32cc
LinuxLinux4.12

References

Timeline

Published
Last Modified
Status
Received

Frequently Asked Questions

What is CVE-2026-90149?
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.
How severe is CVE-2026-90149?
CVE-2026-90149 has a CVSS score of 7.5/10 (HIGH severity).
How do I fix CVE-2026-90149?
Check the vendor references and advisories linked above for patched versions and mitigation guidance. You can also run a Strix scan to test if your systems are affected.

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Source: NVD / NIST