---
cve: "CVE-2025-21850"
severity: "CRITICAL"
cvss: 9.8
epss: "0.4%"
vendor: "Linux"
kev: false
exploited: false
published: "2025-03-12 10:15:17"
tags: [cve, security, critical]
source: tsecurity.de CVE-Dossier
exported: "2026-10-27T10:31:07+01:00"
---

# CVE-2025-21850

> 9.8 CRITICAL

## Beschreibung

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

nvmet: Fix crash when a namespace is disabled

The namespace percpu counter protects pending I/O, and we can
only safely diable the namespace once the counter drop to zero.
Otherwise we end up with a crash when running blktests/nvme/058
(eg for loop transport):

[ 2352.930426] [  T53909] Oops: general protection fault, probably for non-canonical address 0xdffffc0000000005: 0000 [#1] PREEMPT SMP KASAN PTI
[ 2352.930431] [  T53909] KASAN: null-ptr-deref in range [0x0000000000000028-0x000000000000002f]
[ 2352.930434] [  T53909] CPU: 3 UID: 0 PID: 53909 Comm: kworker/u16:5 Tainted: G        W          6.13.0-rc6 #232
[ 2352.930438] [  T53909] Tainted: [W]=WARN
[ 2352.930440] [  T53909] Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.16.3-3.fc41 04/01/2014
[ 2352.930443] [  T53909] Workqueue: nvmet-wq nvme_loop_execute_work [nvme_loop]
[ 2352.930449] [  T53909] RIP: 0010:blkcg_set_ioprio+0x44/0x180

as the queue is already torn down when calling submit_bio();

So we need to init the percpu counter in nvmet_ns_enable(), and
wait for it to drop to zero in nvmet_ns_disable() to avoid having
I/O pending after the namespace has been disabled.

## CNA-Record (Kanon, cvelistV5)

- CNA: **Linux**
- State: PUBLISHED
- Stand: 2026-08-05 11:54:53
- CNA-CVSS: **9.8** (`CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H`)

## CISA-Anreicherung (vulnrichment/ADP)

- CISA-SSVC (Coordinator, v2.0.3):
  - Exploitation: **none**
  - Automatable: **no**
  - Technical Impact: **partial**

## 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 |

## Schwachstellen-Klasse

- **CWE-835** — Loop with Unreachable Exit Condition ('Infinite Loop')
  The product contains an iteration or loop with an exit condition that cannot be reached, i.e., an infinite loop.

## Patch verfügbar (OSV)

- Kernel ≥ 6.13.5

## BSI-Hinweise (deutsch)

- [Dell Secure Connect Gateway: Mehrere Schwachstellen ermöglichen nicht spezifizierten Angriff](https://wid.cert-bund.de/portal/wid/sicherheitshinweis/WID-SEC-W-2025-1439) — _BSI-Einstufung: mittel_
  Ein Angreifer kann mehrere Schwachstellen in Dell Secure Connect Gateway ausnutzen, um einen nicht näher spezifizierten Angriff durchzuführen.
- [Linux Kernel: Mehrere Schwachstellen ermöglichen Denial of Service](https://wid.cert-bund.de/portal/wid/sicherheitshinweis/WID-SEC-W-2025-0545) — _BSI-Einstufung: hoch_
  Ein Angreifer kann mehrere Schwachstellen im Linux Kernel ausnutzen, um einen Denial of Service Zustand herbeizuführen und um nicht näher beschriebene Auswirkungen zu verursachen.

## Referenzen

- <https://git.kernel.org/stable/c/cc0607594f6813342b27c752c6fb6f6eb9980cb5>
- <https://git.kernel.org/stable/c/4082326807072b71496501b6a0c55ffe8d5092a5>

---
_Exportiert aus dem [tsecurity.de CVE-Dossier](https://tsecurity.de/sicherheitsluecken/cve-2025-21850/) · Datenquellen: EUVD (ENISA), NVD, OSV, CISA KEV, FIRST EPSS, Exploit-DB, BSI WID (CSAF)_