---
cve: "CVE-2026-63812"
severity: "HIGH"
cvss: 7.8
epss: "0.2%"
vendor: "Linux"
kev: false
exploited: false
published: "2026-07-19 12:16:54"
tags: [cve, security, high]
source: tsecurity.de CVE-Dossier
exported: "2026-09-20T21:21:36+02:00"
---

# CVE-2026-63812

> 7.8 HIGH

## Beschreibung

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

f2fs: fix incorrect FI_NO_EXTENT handling in __destroy_extent_node()

When __destroy_extent_node() sets the inode flag FI_NO_EXTENT, it does
not reset the length of the largest extent to 0 and update the inode
folio. Since modifications to the extent tree are disallowed afterward,
the cached largest extent may become stale. This can trigger the
following error in xfstests generic/388:

F2FS-fs (dm-0): sanity_check_extent_cache: inode (ino=1761) extent info [220057, 57, 6] is incorrect, run fsck to fix

In the f2fs_drop_inode path, __destroy_extent_node() does not need to
guarantee that et->node_cnt is 0, because concurrency with writeback
is expected in this path, and writeback may update the extent cache.

This patch reverts commit ed78aeebef05 ("f2fs: fix node_cnt race between
extent node destroy and writeback"), and remove the unnecessary zero
check of et->node_cnt.

## CVSS-Vektor

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

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

## Patch verfügbar (OSV)

- Kernel ≥ 6.6.144
- Kernel ≥ 6.12.95
- Kernel ≥ 6.18.38
- Kernel ≥ 7.1.3

## Referenzen

- <https://git.kernel.org/stable/c/7e4d8f98be63f98856a5176b9188dada6e7ba9ee>
- <https://git.kernel.org/stable/c/58a5deb220bcac4c73bf58954c0845644c997487>
- <https://git.kernel.org/stable/c/20190e498057997532c7f186d081011f18e0a462>
- <https://git.kernel.org/stable/c/edf12cbeeeabe799bd2ee21fdb5c336cce6fbad7>
- <https://git.kernel.org/stable/c/1f70ddb28a3c71df124da5fa4040c808116d6bb9>

---
_Exportiert aus dem [tsecurity.de CVE-Dossier](https://tsecurity.de/cve?cve=CVE-2026-63812) · Datenquellen: EUVD (ENISA), NVD, OSV, CISA KEV, FIRST EPSS, Exploit-DB, BSI BITS_