CVE-2026-89685

HIGH

MEDIUM Priority: 0.05 BB Relevance: 75/100

Published: 2026-09-11 Modified: 2026-10-30 First seen: 2026-10-30 Status: active

Attack Surface

Network Low Complexity No Auth No Interaction

CVSS Vector Breakdown

AV: Network

AC: Low

PR: None

UI: None

S: Unchanged

C: None

I: None

A: High

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.

Affected Software (9)

Vendor	Product	Version
Linux	Linux	20b7d86f29d39e8ae19bb29c24ffee70dc385ddf < 7ca44a63d9a554ba7ad05b06d88746eab08b760e
Linux	Linux	20b7d86f29d39e8ae19bb29c24ffee70dc385ddf < 2c9efc6b692a153643d0f204b3c3632cb6b5761e
Linux	Linux	20b7d86f29d39e8ae19bb29c24ffee70dc385ddf < a22ee3a2cadef44f2edeb909ae36bd72450a3a35
Linux	Linux	20b7d86f29d39e8ae19bb29c24ffee70dc385ddf < 04c3e4456fe76e8d7c94171009df3165c3262c51
Linux	Linux	20b7d86f29d39e8ae19bb29c24ffee70dc385ddf < e92e80c5b043108029bc729b30d12c37158fb9cb
Linux	Linux	20b7d86f29d39e8ae19bb29c24ffee70dc385ddf < f9cec313efb2fd18d962aad738a4892bce806016
Linux	Linux	20b7d86f29d39e8ae19bb29c24ffee70dc385ddf < 9843649196221152b6e5d138a3ce859bdaae1d96
Linux	Linux	20b7d86f29d39e8ae19bb29c24ffee70dc385ddf < 09ea3eb9a518565f5bca386e81b993ed8825f5e8
Linux	Linux	5.6