Vulnerability details
CVE-2026-89685
nfsd: fix clock domain mismatch in clients_still_reclaiming()
Official 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.
CVSS scores
| Score | Version | Source | Vector |
|---|---|---|---|
| 7.5High | 3.1 | CVEProject cvelistV5 (CNA) (Linux) | CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H |
Affected products
| Vendor | Product | Versions | Source |
|---|---|---|---|
| Linux | Linux | 5.6 | CVEProject cvelistV5 (CNA) |
| Linux | Linux | 20b7d86f29d39e8ae19bb29c24ffee70dc385ddf ≤ v < 2c9efc6b692a153643d0f204b3c3632cb6b5761e | CVEProject cvelistV5 (CNA) |
| Linux | Linux | 20b7d86f29d39e8ae19bb29c24ffee70dc385ddf ≤ v < a22ee3a2cadef44f2edeb909ae36bd72450a3a35 | CVEProject cvelistV5 (CNA) |
| Linux | Linux | 20b7d86f29d39e8ae19bb29c24ffee70dc385ddf ≤ v < 04c3e4456fe76e8d7c94171009df3165c3262c51 | CVEProject cvelistV5 (CNA) |
| Linux | Linux | 20b7d86f29d39e8ae19bb29c24ffee70dc385ddf ≤ v < 7ca44a63d9a554ba7ad05b06d88746eab08b760e | CVEProject cvelistV5 (CNA) |
| Linux | Linux | 20b7d86f29d39e8ae19bb29c24ffee70dc385ddf ≤ v < f9cec313efb2fd18d962aad738a4892bce806016 | CVEProject cvelistV5 (CNA) |
| Linux | Linux | 20b7d86f29d39e8ae19bb29c24ffee70dc385ddf ≤ v < 9843649196221152b6e5d138a3ce859bdaae1d96 | CVEProject cvelistV5 (CNA) |
| Linux | Linux | 20b7d86f29d39e8ae19bb29c24ffee70dc385ddf ≤ v < 09ea3eb9a518565f5bca386e81b993ed8825f5e8 | CVEProject cvelistV5 (CNA) |
| Linux | Linux | 20b7d86f29d39e8ae19bb29c24ffee70dc385ddf ≤ v < e92e80c5b043108029bc729b30d12c37158fb9cb | CVEProject cvelistV5 (CNA) |
References and advisories
8- https://git.kernel.org/stable/c/7ca44a63d9a554ba7ad05b06d88746eab08b760e
- https://git.kernel.org/stable/c/2c9efc6b692a153643d0f204b3c3632cb6b5761e
- https://git.kernel.org/stable/c/a22ee3a2cadef44f2edeb909ae36bd72450a3a35
- https://git.kernel.org/stable/c/04c3e4456fe76e8d7c94171009df3165c3262c51
- https://git.kernel.org/stable/c/e92e80c5b043108029bc729b30d12c37158fb9cb
- https://git.kernel.org/stable/c/f9cec313efb2fd18d962aad738a4892bce806016
- https://git.kernel.org/stable/c/9843649196221152b6e5d138a3ce859bdaae1d96
- https://git.kernel.org/stable/c/09ea3eb9a518565f5bca386e81b993ed8825f5e8
Details
- Published
- 2026-09-11
- Last updated
- 2026-10-30
- State
- Published
- Assigner (CNA)
- Linux
Exploit prediction (EPSS)
SSVC assessment (CISA)
- Automatable
- Yes
- Exploitation
- None
- Technical impact
- Partial
Weaknesses (CWE)
- —