NFSv4/flexfiles: fix NULL dereference for NFSv4.0 data servers
Key facts
- Attack vector
- Network
- Privileges required
- None
- User interaction
- None
- Attack complexity
- Low
- Impact type
- —
- Confidentiality · integrity · availability
- None · None · High
- Fix status
- Partial Red Hat: 6 without a fix
Attack profile from CVSS 3.1 · CNA. Fix status from CNA and Red Hat.
Summary
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.
Why it matters now
SSVC decision points
Not available: CISA has not published SSVC decision points for this record.
Affected products
Remediation
- Fix · CNA Linux (Linux) Fixed in 6.1.191, 6.6.160, 6.12.114, 6.18.52, 7.2.6, 7.3
Vendor assessments
Red Hat
Red Hat rating: Moderate. Red Hat's page for this CVE →
| Product | Status | Plan or fix |
|---|---|---|
| Red Hat Enterprise Linux 10 | Affected | No fix yet: Fix deferred |
| Red Hat Enterprise Linux 7 | Affected | No fix yet: Fix deferred |
| Red Hat Enterprise Linux 8 | Affected | No fix yet: Fix deferred |
| Red Hat Enterprise Linux 9 | Affected | No fix yet: Fix deferred |
| Red Hat OpenShift Container Platform 4 | Affected | No fix yet: Fix deferred |
| Red Hat OpenShift Container Platform 5 | Affected | No fix yet: Fix deferred |
Not affected: 1 product
- Red Hat Enterprise Linux 6
Timeline
- 2026-10-02 Threatist record created from CVE-2026-90149
- 2026-10-03 Alias added: GHSA-5pv5-p9q3-rvv6
- 2026-10-13 Affected versions changed · Red Hat
- 2026-10-13 CVSS score added · Red Hat
- 2026-10-19 Fix available: Linux/[email protected] · CNA
- 2026-10-21 Fix available: Linux/Linux@336b6da10021c69a8f273bbacdf7432fdc89a06f, Linux/Linux@5527af72b0100c94287bfec901b6313eeac567ca, Linux/[email protected] +1 · CNA
- 2026-10-21 2 new references · CNA
- 2026-10-30 Fix available: Linux/[email protected], Linux/Linux@e55d7fec8a9290f73032ee34c35dd68532809633 · CNA
- 2026-10-30 1 new reference · CNA
- 2026-10-30 Affected versions changed · Red Hat
- 2026-10-31 EPSS moved to the 50th–90th percentile
References
Other 6
- https://git.kernel.org/stable/c/e55d7fec8a9290f73032ee34c35dd68532809633
- https://git.kernel.org/stable/c/336b6da10021c69a8f273bbacdf7432fdc89a06f
- https://git.kernel.org/stable/c/5527af72b0100c94287bfec901b6313eeac567ca
- https://git.kernel.org/stable/c/163c16e01f53fc8eb8d0f3484ae6c382265ecbbd
- https://git.kernel.org/stable/c/436a214514e24103159aea455147d58b44a8a585
- https://git.kernel.org/stable/c/2b03ebbf8d5e8f6af4ecd6c65375232dd1ec32cc
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Sources
- CVE-2026-90149 · CVE Program
- CVE-2026-90149 · NVD
- FIRST EPSS
- GHSA-5pv5-p9q3-rvv6 · GitHub Advisory Database · CC BY 4.0
- CVE-2026-90149 · Red Hat security data · CC BY 4.0
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