---
cve: "CVE-2026-53399"
severity: "CRITICAL"
cvss: 9.8
epss: "0.5%"
vendor: "Linux"
kev: false
exploited: false
published: "2026-07-19 12:02:00"
tags: [cve, security, critical]
source: tsecurity.de CVE-Dossier
exported: "2026-09-21T08:11:44+02:00"
---

# CVE-2026-53399

> 9.8 CRITICAL

## Beschreibung

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

nfsd: release layout stid on setlease failure

nfs4_alloc_stid() publishes the new stid into cl->cl_stateids via
idr_alloc_cyclic() under cl_lock before returning to
nfsd4_alloc_layout_stateid(). When nfsd4_layout_setlease() then
fails, the error path frees the layout stateid directly with
kmem_cache_free() without ever calling idr_remove(), leaving the
IDR slot pointing at freed slab memory. Any subsequent IDR walker
(states_show, client teardown) dereferences the dangling pointer.

The correct teardown for an IDR-published stid is nfs4_put_stid(),
which removes the IDR slot under cl_lock, dispatches sc_free
(nfsd4_free_layout_stateid) to release ls->ls_file via
nfsd4_close_layout(), and drops the nfs4_file reference in its
tail.

A second issue blocks that switch: nfsd4_free_layout_stateid()
unconditionally inspects ls->ls_fence_work via
delayed_work_pending() under ls_lock, but
INIT_DELAYED_WORK(&ls->ls_fence_work, ...) currently runs only
after the setlease call. On the setlease-failure path the
destructor would touch an uninitialized delayed_work.

    nfsd4_alloc_layout_stateid()
      nfs4_alloc_stid()           /* idr_alloc_cyclic under cl_lock */
      nfsd4_layout_setlease()     /* fails */
        nfs4_put_stid()
          nfsd4_free_layout_stateid()
            delayed_work_pending(&ls->ls_fence_work)  /* needs INIT */
            nfsd4_close_layout()  /* nfsd_file_put(ls->ls_file) */
          put_nfs4_file()

Fix by hoisting the ls_fenced / ls_fence_delay / INIT_DELAYED_WORK
initialization above the nfsd4_layout_setlease() call, and replace
the manual nfsd_file_put + put_nfs4_file + kmem_cache_free cleanup
with a single nfs4_put_stid(stp).

## CVSS-Vektor

```
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
```

| Metrik | Wert | Bewertung |
|---|---|---|
| AV Angriffsvektor | Netzwerk | bad |
| AC Komplexität | Gering | bad |
| PR Privilegien | Keine | bad |
| UI Interaktion | Keine | bad |
| S Scope | Unverändert | good |
| C Vertraulichkeit | Hoch | bad |
| I Integrität | Hoch | bad |
| A Verfügbarkeit | Hoch | bad |

## Patch verfügbar (OSV)

- Kernel ≥ 5.10.261
- Kernel ≥ 5.15.212
- Kernel ≥ 6.1.178
- Kernel ≥ 6.6.145
- Kernel ≥ 6.12.96
- Kernel ≥ 6.18.39
- Kernel ≥ 7.1.3

## Referenzen

- <https://git.kernel.org/stable/c/d788ef40a7517d22c97ab01700e4ae4c611b6f2f>
- <https://git.kernel.org/stable/c/2e0a5d6d62600b8c614d1b55e50ef94035d6adf9>
- <https://git.kernel.org/stable/c/7bbb7ce74051c8be4b69ff44ce3db370600dae61>
- <https://git.kernel.org/stable/c/48a586e382e4db1dbf958d44b63e081df5f8ed04>
- <https://git.kernel.org/stable/c/d369e5edfaaf83a448016e2f1da392b2174be801>
- <https://git.kernel.org/stable/c/8dee7c278f1c2b5bb80e17a6281c3812fc8b0cdd>
- <https://git.kernel.org/stable/c/83c2b7797742339bb768f83935f7ca33950db138>
- <https://git.kernel.org/stable/c/30d55c8aabb261bc3f427d6b9aae7ef6206063f9>

---
_Exportiert aus dem [tsecurity.de CVE-Dossier](https://tsecurity.de/cve?cve=CVE-2026-53399) · Datenquellen: EUVD (ENISA), NVD, OSV, CISA KEV, FIRST EPSS, Exploit-DB, BSI BITS_