---
cve: "CVE-2026-63814"
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: "2026-09-21T02:26:59+02:00"
---

# CVE-2026-63814

> 7.8 HIGH

## Beschreibung

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

f2fs: validate ACL entry sizes in f2fs_acl_from_disk()

f2fs_acl_count() only validates the aggregate ACL xattr length. A
malformed ACL can still place ACL_USER or ACL_GROUP in a slot that only
contains struct f2fs_acl_entry_short bytes, and f2fs_acl_from_disk()
then reads entry->e_id before verifying that a full entry fits.

Require a short entry before reading e_tag and e_perm, and require a
full entry before reading e_id for ACL_USER and ACL_GROUP. Return
-EFSCORRUPTED from these new truncated-entry checks, while keeping the
pre-existing -EINVAL paths unchanged.

Validation reproduced this kernel report:
KASAN slab-out-of-bounds in __f2fs_get_acl+0x6fb/0x7e0
RIP: 0033:0x7f4b835ea7aa
The buggy address belongs to the object at ffff888114589960 which belongs
to the cache kmalloc-8 of size 8
The buggy address is located 0 bytes to the right of allocated 8-byte
region [ffff888114589960, ffff888114589968)
Read of size 4
Call trace:
  dump_stack_lvl+0x66/0xa0 (?:?)
  print_report+0xce/0x630 (?:?)
  __f2fs_get_acl+0x6fb/0x7e0 (fs/f2fs/acl.c:169)
  srso_alias_return_thunk+0x5/0xfbef5 (?:?)
  __virt_addr_valid+0x224/0x430 (?:?)
  kasan_report+0xe0/0x110 (?:?)
  __f2fs_get_acl+0x5/0x7e0 (fs/f2fs/acl.c:169)
  __get_acl+0x281/0x380 (?:?)
  vfs_get_acl+0x10b/0x190 (?:?)
  do_get_acl+0x2a/0x410 (?:?)
  do_get_acl+0x9/0x410 (?:?)
  do_getxattr+0xe8/0x260 (?:?)
  filename_getxattr+0xd1/0x140 (?:?)
  do_getname+0x2d/0x2d0 (?:?)
  path_getxattrat+0x16c/0x200 (?:?)
  lock_release+0xc8/0x290 (?:?)
  cgroup_update_frozen+0x9d/0x320 (?:?)
  lockdep_hardirqs_on_prepare+0xea/0x1a0 (?:?)
  trace_hardirqs_on+0x1a/0x170 (?:?)
  _raw_spin_unlock_irq+0x28/0x50 (?:?)
  do_syscall_64+0x115/0x6a0 (arch/x86/entry/syscall_64.c:87)
  entry_SYSCALL_64_after_hwframe+0x77/0x7f (?:?)

## 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 ≥ 5.10.260
- Kernel ≥ 5.15.211
- Kernel ≥ 6.1.177
- Kernel ≥ 6.6.144
- Kernel ≥ 6.12.95
- Kernel ≥ 6.18.38
- Kernel ≥ 7.1.3

## Referenzen

- <https://git.kernel.org/stable/c/733cd8474e6d763d75ed96f3f2b98a25480cf2b9>
- <https://git.kernel.org/stable/c/4e2a96ec7236e248e706850568e0a925fd21b588>
- <https://git.kernel.org/stable/c/442ca20c54038e2400cf28aaa944cf1de2c8e65d>
- <https://git.kernel.org/stable/c/1ddf3fd21c4c652f9cab5552515c04a166662306>
- <https://git.kernel.org/stable/c/aba4f94ac1832c7299c33e1b4fe5f87eef6dc8f1>
- <https://git.kernel.org/stable/c/ff83de56882cb8466184d322abece2589258ca56>
- <https://git.kernel.org/stable/c/5d8a39649947a4e86c8fbc682d7fc0041b8d109a>
- <https://git.kernel.org/stable/c/c4810ada31e80cbe4011467c4f3b1e93f94134f3>

---
_Exportiert aus dem [tsecurity.de CVE-Dossier](https://tsecurity.de/cve?cve=CVE-2026-63814) · Datenquellen: EUVD (ENISA), NVD, OSV, CISA KEV, FIRST EPSS, Exploit-DB, BSI BITS_