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CRITICAL

CVE-2026-89708

CVSS v3

9.8

CRITICAL

EPSS Score

0.7 %

exploit probability, as of 2026-09-28

CISA KEV

No

known exploited

Exploitation

—

SSVC status

Description

In the Linux kernel, the following vulnerability has been resolved: nfsd: RCU-protect cl_cb_session to fix use-after-free on session teardown After a DESTROY_SESSION the per-session teardown path can free a session while rpciod still holds an inflight callback rpc_task that dereferences clp->cl_cb_session. nfsd4_probe_callback_sync() flushes cl_callback_wq, but once nfsd4_run_cb_work() has called rpc_call_async() the rpc_task lives on rpciod; flushing the workqueue does not wait for it. rpc_

Technical details

Published
2026-09-11
Last Modified
2026-09-13

Frequently asked questions

What is CVE-2026-89708?

In the Linux kernel, the following vulnerability has been resolved: nfsd: RCU-protect cl_cb_session to fix use-after-free on session teardown After a DESTROY_SESSION the per-session teardown path can free a session while rpciod still holds an inflight callback rpc_task that dereferences clp->cl_cb_session. nfsd4_probe_callback_sync() flushes cl_callback_wq, but once nfsd4_run_cb_work() has called rpc_call_async() the rpc_task lives on rpciod; flushing the workqueue does not wait for it. rpc_

Is CVE-2026-89708 actively exploited?

Active exploitation of CVE-2026-89708 has not been confirmed. Its EPSS score was 0.7% on 2026-09-28, the estimated probability of exploitation in the next 30 days.

What is the CVSS score for CVE-2026-89708?

CVE-2026-89708 has a CVSS v3 base score of 9.8 (CRITICAL severity).

Is CVE-2026-89708 affecting your environment?

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