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CVE-2026-89685

7.5 · HIGH

In the Linux kernel, the following vulnerability has been resolved: nfsd: fix clock domain mismatch in clients_still_reclaiming() clients_still_reclaiming() computes a deadline from nn->boot_time…

Published Sep 11, 2026EPSS 0.61%

Overview

CVE-2026-89685 is a high-severity vulnerability. It was published on September 11, 2026 and has a CVSS 3.1 base score of 7.5 (HIGH).

This vulnerability has a CVSS 3.1 base score of 7.5, rated HIGH. It can be exploited remotely over the network. No authentication or special privileges are required for exploitation.

Technical description

In the Linux kernel, the following vulnerability has been resolved:

nfsd: fix clock domain mismatch in clients_still_reclaiming()

clients_still_reclaiming() computes a deadline from nn->boot_time

(CLOCK_REALTIME, ~1.7 billion) but compares it against

ktime_get_boottime_seconds() (CLOCK_BOOTTIME, seconds since boot).

The comparison is always false — it would take ~54 years of uptime

for BOOTTIME to exceed the REALTIME-derived deadline.

This means any client can hold the server in grace indefinitely by

sending CLAIM_PREVIOUS OPEN requests, blocking all non-reclaim

operations for all other clients.

Add boot_time_bt (CLOCK_BOOTTIME) alongside the existing boot_time

and use it for the deadline computation. boot_time (CLOCK_REALTIME)

is preserved for its cl_boot clientid-nonce role.

Remediation

Check the references section for vendor advisories, patches, and mitigation guidance. If immediate patching is not possible, review the CVSS vector to understand the attack surface and apply compensating controls such as network segmentation or access restrictions.

References

Refgit.kernel.org/stable/c/04c3e4456fe76e8d7c94171009df3165c3262c51Refgit.kernel.org/stable/c/09ea3eb9a518565f5bca386e81b993ed8825f5e8Refgit.kernel.org/stable/c/2c9efc6b692a153643d0f204b3c3632cb6b5761eRefgit.kernel.org/stable/c/7ca44a63d9a554ba7ad05b06d88746eab08b760eRefgit.kernel.org/stable/c/9843649196221152b6e5d138a3ce859bdaae1d96Refgit.kernel.org/stable/c/a22ee3a2cadef44f2edeb909ae36bd72450a3a35Refgit.kernel.org/stable/c/e92e80c5b043108029bc729b30d12c37158fb9cbRefgit.kernel.org/stable/c/f9cec313efb2fd18d962aad738a4892bce806016

How CyberStrike helps

Frequently asked questions

What is CVE-2026-89685?

CVE-2026-89685 is a high-severity vulnerability. It was published on September 11, 2026 and has a CVSS 3.1 base score of 7.5 (HIGH).

How severe is CVE-2026-89685?

This vulnerability has a CVSS 3.1 base score of 7.5, rated HIGH. It can be exploited remotely over the network. No authentication or special privileges are required for exploitation.

How do I fix or remediate CVE-2026-89685?

Check the references section for vendor advisories, patches, and mitigation guidance. If immediate patching is not possible, review the CVSS vector to understand the attack surface and apply compensating controls such as network segmentation or access restrictions.

How can CyberStrike help with CVE-2026-89685?

CyberStrike is an open-source, AI-augmented pentesting engine. Rather than flag a version number, it tests whether an issue like CVE-2026-89685 is actually reachable in your own applications and APIs, then verifies each finding before reporting it. That tells you if the weakness is a real, exploitable risk in your environment or a false positive you can safely deprioritize.

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