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Fencer Intel
high 7.8

CVE-2026-63814 json

f2fs: validate ACL entry sizes in f2fs_acl_from_disk()

published 3mo ago modified yesterday also EUVD-2026-45480

cvss
7.8
version 3.1, CNA
cisa kev
Not listed
not in CISA's catalog
epss
0.1%
EPSS 0.1% chance of exploitation in 30 days, percentile 2%
public exploits
0
none known

Summary

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 (?:?)

Patch / fix

  • Linux Linux 5.10.260, 5.15.211, 6.1.177, 6.6.144, 6.12.95, 6.18.38, 7.1.3, 7.2
  • linux Debian 12 6.1.177-1
  • linux Debian 13 6.12.95-1
  • linux Debian 14 7.1.3-1

debian advisories DEBIAN-CVE-2026-63814

  • linux Ubuntu 22.04 LTS 5.15.0-198.208
  • linux Ubuntu 24.04 LTS 6.8.0-147.147
  • linux Ubuntu 26.04 LTS 7.0.0-31.31
  • linux-aws Ubuntu 22.04 LTS 5.15.0-1117.124
  • linux-aws Ubuntu 24.04 LTS 6.8.0-1067.70
  • linux-aws Ubuntu 26.04 LTS 7.0.0-1012.12
  • linux-gcp Ubuntu 22.04 LTS 5.15.0-1118.128
  • linux-gcp Ubuntu 24.04 LTS 6.8.0-1071.79

ubuntu advisories UBUNTU-CVE-2026-63814

Ubuntu security data © Canonical Ltd., from https://github.com/canonical/ubuntu-security-notices via OSV; changed: normalised to fixed package versions per release. CC BY-SA 4.0

  • kernel-source openSUSE Tumbleweed 7.1.4-1.1

opensuse advisories openSUSE-SU-2026:11339-1

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Vendor advisories

What the vendors themselves say about their products: affected, fixed or not affected, and what to do.

red hat product security vex CVE-2026-63814 updated

kernel: f2fs: validate ACL entry sizes in f2fs_acl_from_disk()

  • Red Hat Enterprise Linux 6 perf, kernel, python-perf, kernel-kdump, kernel-firmware, kernel-bootwrapper, +1 more Red Hat Enterprise Linux 7 perf, kernel, bpftool, kernel-rt, python-perf, kernel-kdump, +8 more Red Hat Enterprise Linux 8 perf, kernel, bpftool, kernel-rt, kernel-core, kernel-tools, +29 more Red Hat Enterprise Linux 9 rv, perf, rtla, kernel, bpftool, libperf, +83 more Red Hat Enterprise Linux 10 kernel
    not affected: vulnerable code not present

Red Hat CSAF VEX © Red Hat, Inc., from https://security.access.redhat.com/data/csaf/v2/vex/; changed: reduced to product statuses and remediations. CC BY 4.0 · csaf

Exploit prediction

0.13% chance of exploitation in the next 30 days, higher than 2% of all scored CVEs (FIRST EPSS, 2026-11-11).

CVSS scores

assigned by version score vector
CNA 3.1 7.8 CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H

Affected products

  • Linux Linux

Classification

Weakness
Technology feeds

References

Sources

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