---
cve: "CVE-2026-63816"
severity: "HIGH"
cvss: 7.8
epss: "0.1%"
vendor: "Linux"
kev: false
exploited: false
published: "2026-07-19 12:16:54"
tags: [cve, security, high]
source: tsecurity.de CVE-Dossier
exported: "2026-09-20T20:04:06+02:00"
---

# CVE-2026-63816

> 7.8 HIGH

## Beschreibung

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

f2fs: atomic: fix UAF issue on f2fs_inode_info.atomic_inode

- ioctl(F2FS_IOC_GARBAGE_COLLECT_RANGE)		- shrink
 - f2fs_gc
  - gc_data_segment
   - ra_data_block(cow_inode)
    - mapping = F2FS_I(inode)->atomic_inode->i_mapping
    : f2fs_is_cow_file(cow_inode) is true
						 - f2fs_evict_inode(atomic_inode)
						  - clear_inode_flag(fi->cow_inode, FI_COW_FILE)
						  - F2FS_I(fi->cow_inode)->atomic_inode = NULL
						  ...
						  - truncate_inode_pages_final(atomic_inode)
    - f2fs_grab_cache_folio(mapping)
    : create folio in atomic_inode->mapping
						  - clear_inode(atomic_inode)
						   - BUG_ON(atomic_inode->i_data.nrpages)

We need to add a reference on fi->atomic_inode before using its mapping
field during garbage collection, otherwise, it will cause UAF issue.

## 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 ≥ 6.6.145
- Kernel ≥ 6.12.96
- Kernel ≥ 6.18.39
- Kernel ≥ 7.1.3

## Referenzen

- <https://git.kernel.org/stable/c/7d3ae21783e5914c1761ac7d63f882d3d70800e9>
- <https://git.kernel.org/stable/c/56038756aae68312df00d4aa1d97e51ef3aca725>
- <https://git.kernel.org/stable/c/a499f77c06050a28c897bdbd86cd2f0721ae0743>
- <https://git.kernel.org/stable/c/a805fec35c201c59643ddcde713bce4051c8ee27>
- <https://git.kernel.org/stable/c/e0288584baa5dc41df4a829a023c4c1b33fe53d7>

---
_Exportiert aus dem [tsecurity.de CVE-Dossier](https://tsecurity.de/cve?cve=CVE-2026-63816) · Datenquellen: EUVD (ENISA), NVD, OSV, CISA KEV, FIRST EPSS, Exploit-DB, BSI BITS_