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Fencer Vulns
medium 5.5

CVE-2026-46002 json

ext2: reject inodes with zero i_nlink and valid mode in ext2_iget()

published 2026-05-27 5 mo ago modified 2026-06-17 4 mo ago also EUVD-2026-32298

cvss
5.5
version 3.1, NVD
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:

ext2: reject inodes with zero i_nlink and valid mode in ext2_iget()

ext2_iget() already rejects inodes with i_nlink == 0 when i_mode is zero or i_dtime is set, treating them as deleted. However, the case of i_nlink == 0 with a non-zero mode and zero dtime slips through. Since ext2 has no orphan list, such a combination can only result from filesystem corruption - a legitimate inode deletion always sets either i_dtime or clears i_mode before freeing the inode.

A crafted image can exploit this gap to present such an inode to the VFS, which then triggers WARN_ON inside drop_nlink() (fs/inode.c) via ext2_unlink(), ext2_rename() and ext2_rmdir():

WARNING: CPU: 3 PID: 609 at fs/inode.c:336 drop_nlink+0xad/0xd0 fs/inode.c:336 CPU: 3 UID: 0 PID: 609 Comm: syz-executor Not tainted 6.12.77+ #1 Call Trace: <TASK> inode_dec_link_count include/linux/fs.h:2518 [inline] ext2_unlink+0x26c/0x300 fs/ext2/namei.c:295 vfs_unlink+0x2fc/0x9b0 fs/namei.c:4477 do_unlinkat+0x53e/0x730 fs/namei.c:4541 __x64_sys_unlink+0xc6/0x110 fs/namei.c:4587 do_syscall_64+0xf5/0x220 arch/x86/entry/common.c:78 entry_SYSCALL_64_after_hwframe+0x77/0x7f </TASK>

WARNING: CPU: 0 PID: 646 at fs/inode.c:336 drop_nlink+0xad/0xd0 fs/inode.c:336 CPU: 0 UID: 0 PID: 646 Comm: syz.0.17 Not tainted 6.12.77+ #1 Call Trace: <TASK> inode_dec_link_count include/linux/fs.h:2518 [inline] ext2_rename+0x35e/0x850 fs/ext2/namei.c:374 vfs_rename+0xf2f/0x2060 fs/namei.c:5021 do_renameat2+0xbe2/0xd50 fs/namei.c:5178 __x64_sys_rename+0x7e/0xa0 fs/namei.c:5223 do_syscall_64+0xf5/0x220 arch/x86/entry/common.c:78 entry_SYSCALL_64_after_hwframe+0x77/0x7f </TASK>

WARNING: CPU: 0 PID: 634 at fs/inode.c:336 drop_nlink+0xad/0xd0 fs/inode.c:336 CPU: 0 UID: 0 PID: 634 Comm: syz-executor Not tainted 6.12.77+ #1 Call Trace: <TASK> inode_dec_link_count include/linux/fs.h:2518 [inline] ext2_rmdir+0xca/0x110 fs/ext2/namei.c:311 vfs_rmdir+0x204/0x690 fs/namei.c:4348 do_rmdir+0x372/0x3e0 fs/namei.c:4407 __x64_sys_unlinkat+0xf0/0x130 fs/namei.c:4577 do_syscall_64+0xf5/0x220 arch/x86/entry/common.c:78 entry_SYSCALL_64_after_hwframe+0x77/0x7f </TASK>

Extend the existing i_nlink == 0 check to also catch this case, reporting the corruption via ext2_error() and returning -EFSCORRUPTED. This rejects the inode at load time and prevents it from reaching any of the namei.c paths.

Found by Linux Verification Center (linuxtesting.org) with Syzkaller.

Patch / fix

  • Linux Linux 5.10.258, 5.15.209, 6.1.175, 6.6.140, 6.12.86, 6.18.27, 7.0.4, 7.1
  • linux Debian 12 6.1.176-1
  • linux Debian 13 6.12.86-1
  • linux Debian 14 7.0.4-1

debian advisories DEBIAN-CVE-2026-46002

  • linux Ubuntu 22.04 LTS 5.15.0-186.196
  • linux Ubuntu 24.04 LTS 6.8.0-136.136
  • linux Ubuntu 26.04 LTS 7.0.0-27.27
  • linux-aws Ubuntu 22.04 LTS 5.15.0-1112.119
  • linux-aws Ubuntu 24.04 LTS 6.8.0-1061.64
  • linux-aws Ubuntu 26.04 LTS 7.0.0-1008.8
  • linux-gcp Ubuntu 22.04 LTS 5.15.0-1112.122
  • linux-gcp Ubuntu 24.04 LTS 6.8.0-1064.72

ubuntu advisories UBUNTU-CVE-2026-46002

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 7.0.11-1.1

opensuse advisories openSUSE-SU-2026:10954-1

  • kernel Azure Linux 3.0 6.6.141.1-1

azure linux advisories AZL-88626

Azure Linux vulnerability data, Copyright (c) Microsoft Corporation, from https://github.com/microsoft/AzureLinuxVulnerabilityData via OSV, under the MIT licence; changed: normalised to fixed package versions per release. MIT

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-2026-46002 updated cvss 5.5

kernel: ext2: reject inodes with zero i_nlink and valid mode in ext2_iget()

  • Red Hat Enterprise Linux 6 perf, kernel, python-perf, kernel-kdump, kernel-firmware, kernel-bootwrapper, +1 more
    affected: no fix planned “Out of support scope”
  • 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

0.12% chance of exploitation in the next 30 days, higher than 2% of all scored CVEs (FIRST EPSS, 2026-11-08).

CVSS scores

assigned by version score vector
NVD 3.1 5.5 CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H

Affected products

  • Linux Linux

Classification

Technology feeds

References

Sources

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