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Fencer Vulns
high 7.8

CVE-2023-53311 json

nilfs2: fix use-after-free of nilfs_root in dirtying inodes via iput

published 2025-09-16 13 mo ago modified 2026-08-05 3 mo ago also EUVD-2023-59950

cvss
7.8
version 3.1, CNA
cisa kev
Not listed
not in CISA's catalog
epss
0.2%
EPSS 0.2% chance of exploitation in 30 days, percentile 5%
public exploits
0
none known

Summary

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

nilfs2: fix use-after-free of nilfs_root in dirtying inodes via iput

During unmount process of nilfs2, nothing holds nilfs_root structure after nilfs2 detaches its writer in nilfs_detach_log_writer(). Previously, nilfs_evict_inode() could cause use-after-free read for nilfs_root if inodes are left in "garbage_list" and released by nilfs_dispose_list at the end of nilfs_detach_log_writer(), and this bug was fixed by commit 9b5a04ac3ad9 ("nilfs2: fix use-after-free bug of nilfs_root in nilfs_evict_inode()").

However, it turned out that there is another possibility of UAF in the call path where mark_inode_dirty_sync() is called from iput():

nilfs_detach_log_writer() nilfs_dispose_list() iput() mark_inode_dirty_sync() __mark_inode_dirty() nilfs_dirty_inode() __nilfs_mark_inode_dirty() nilfs_load_inode_block() --> causes UAF of nilfs_root struct

This can happen after commit 0ae45f63d4ef ("vfs: add support for a lazytime mount option"), which changed iput() to call mark_inode_dirty_sync() on its final reference if i_state has I_DIRTY_TIME flag and i_nlink is non-zero.

This issue appears after commit 28a65b49eb53 ("nilfs2: do not write dirty data after degenerating to read-only") when using the syzbot reproducer, but the issue has potentially existed before.

Fix this issue by adding a "purging flag" to the nilfs structure, setting that flag while disposing the "garbage_list" and checking it in __nilfs_mark_inode_dirty().

Unlike commit 9b5a04ac3ad9 ("nilfs2: fix use-after-free bug of nilfs_root in nilfs_evict_inode()"), this patch does not rely on ns_writer to determine whether to skip operations, so as not to break recovery on mount. The nilfs_salvage_orphan_logs routine dirties the buffer of salvaged data before attaching the log writer, so changing __nilfs_mark_inode_dirty() to skip the operation when ns_writer is NULL will cause recovery write to fail. The purpose of using the cleanup-only flag is to allow for narrowing of such conditions.

Patch / fix

  • Linux Linux 4.14.323, 4.19.292, 5.4.254, 5.10.191, 5.15.127, 6.1.46, 6.4.11, 6.5
  • linux Debian 12 6.1.52-1
  • linux Debian 14, Debian 13 6.4.11-1

debian advisories DEBIAN-CVE-2023-53311

  • linux Ubuntu 20.04 LTS 5.4.0-169.187
  • linux Ubuntu 22.04 LTS 5.15.0-91.101
  • linux-aws Ubuntu 20.04 LTS 5.4.0-1116.126
  • linux-aws Ubuntu 22.04 LTS 5.15.0-1051.56
  • linux-gcp Ubuntu 20.04 LTS 5.4.0-1120.129
  • linux-gcp Ubuntu 22.04 LTS 5.15.0-1048.56
  • linux-gke Ubuntu 22.04 LTS 5.15.0-1048.53
  • linux-ibm Ubuntu 20.04 LTS 5.4.0-1063.68

ubuntu advisories UBUNTU-CVE-2023-53311

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-rt Real Time Module 15 SP7 6.4.0-150700.7.22.1
  • kernel-syms-rt Real Time Module 15 SP7 6.4.0-150700.7.22.1
  • kernel-source-rt Real Time Module 15 SP7 6.4.0-150700.7.22.1
  • kernel-azure SLE Module for Public Cloud 15 SP7 6.4.0-150700.20.18.1
  • kernel-syms-azure SLE Module for Public Cloud 15 SP7 6.4.0-150700.20.18.1
  • kernel-source-azure SLE Module for Public Cloud 15 SP7 6.4.0-150700.20.18.1
  • kernel-64kb SLE Module for Basesystem 15 SP7 6.4.0-150700.53.22.1
  • kernel-syms SLE Module for Development Tools 15 SP7 6.4.0-150700.53.22.1

suse advisories SUSE-SU-2025:4141-1SUSE-SU-2025:4132-1SUSE-SU-2025:4057-1SUSE-SU-2025:20870-1SUSE-SU-2025:3761-1SUSE-SU-2025:20898-1

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-2023-53311 updated

kernel: nilfs2: fix use-after-free of nilfs_root in dirtying inodes via iput

  • 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

CISA SSVC

Exploitation
none
Automatable
no
Technical impact
total
Assessed
9 mo ago

Exploit prediction

0.16% chance of exploitation in the next 30 days, higher than 5% of all scored CVEs (FIRST EPSS, 2026-11-08).

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
CISA ADP 3.1 7.8 CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
NVD 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

Fencer Vulns keeps one entry per vulnerability: the CVE id wins, then GHSA, and records that alias each other are merged, except that two CVEs always keep separate entries. The same data is available as JSON.