SEPTEMBER 14, 2026
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Case File

CVE-2026-89685

HIGH · CVSS 7.5 EPSS 0.43%

Source: NVD + CISA KEV + EPSS · Published 2026-09-11 · Last synced 2026-09-14

CyberRota Analysis

AI-Generated

The vulnerability in the Linux kernel affects the NFS server, allowing clients to indefinitely hold the server in a grace period by sending CLAIM_PREVIOUS OPEN requests. This misconfiguration in deadline computation can block all non-reclaim operations for other clients, potentially leading to denial-of-service conditions. Organizations using Linux-based systems with NFS services should prioritize addressing this issue to ensure operational continuity and prevent service disruptions.

CVE
CVE-2026-89685
Severity
HIGH
CVSS
7.5
EPSS
0.43%
Linux

Original NVD 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.