CVE-2026-46002 - Vulnerability Details

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

Description

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.

Published: 2026-05-27

Score: n/a

EPSS: n/a

KEV: No

Impact:

Action:

Analysis

Impact

When a corrupted inode on an ext2 filesystem has zero link count, a non‑zero mode and no deletion time, ext2_iget() fails to reject it. The kernel then proceeds to the VFS and triggers a WARN_ON in drop_nlink() during unlink, rename or rmdir. Repeated execution of these paths can destabilise the kernel and eventually lead to a crash, resulting in denial of service.

Affected Systems

All Linux kernel versions that use the ext2 filesystem before the advertised fix are affected. The issue appears in the ext2 subsystem of the kernel, so any host that mounts ext2 or ext3 partitions with such corrupted inodes could be impacted.

Risk and Exploitability

The exploit requires a crafted ext2 image that contains a malformed inode. An attacker with the ability to control the contents of such an image or who can mount a malicious filesystem locally can trigger the warning. The EPSS score is not available and the vulnerability is not in the CISA KEV catalog. While the probability of exploitation is uncertain, the impact of a kernel panic makes the risk significant for systems that cannot immediately apply the patch.

Default status is the baseline for the product, each version can override it (e.g. patched versions marked unaffected).

Vendor Product Default status Versions

Linux

unaffected

Version	Status	Constraints
`1da177e4c3f41524e886b7f1b8a0c1fc7321cac2`	affected	< 32e0b925572686399243834ec99e2a9d85c62eae
`1da177e4c3f41524e886b7f1b8a0c1fc7321cac2`	affected	< d3af04a43db86379df7438bf8bade71685b8a239
`1da177e4c3f41524e886b7f1b8a0c1fc7321cac2`	affected	< 2dde6377ab2e46bb80cf066c659ef016f3ad7a9b
`1da177e4c3f41524e886b7f1b8a0c1fc7321cac2`	affected	< 470264bbec499e276a89a6431144ae58f411ea4d
`1da177e4c3f41524e886b7f1b8a0c1fc7321cac2`	affected	< 25947cc5b2374cd5bf627fe3141496444260d04f

Linux

affected

Version	Status	Constraints
`2.6.12`	affected	—
`0`	unaffected	< 2.6.12
`6.6.140`	unaffected	≤ 6.6.*
`6.12.86`	unaffected	≤ 6.12.*
`6.18.27`	unaffected	≤ 6.18.*
`7.0.4`	unaffected	≤ 7.0.*
`7.1-rc1`	unaffected	≤ *

No data.

No data available yet.

Remediation

No vendor fix or workaround currently provided.

OpenCVE Recommended Actions

Upgrade your system to a Linux kernel release that includes the ext2 inode validation fix; check kernel changelogs for the relevant patch.
If you cannot upgrade, run full filesystem checks with fsck -fy on all ext2 partitions to locate and repair corrupted inodes, then reboot to clear any residual issues.
Enable monitoring of kernel logs for the phrases "WARNING: ... drop_nlink" and alert on repeated occurrences, so that you can detect and contain potential corruption before it escalates.

Generated by OpenCVE AI on May 27, 2026 at 17:02 UTC.

Tracking

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Advisories

No advisories yet.

No CVSS v4.0

No CVSS v3.1

No CVSS v3.0

No CVSS v2

This CVE is not in the KEV list.

No EPSS score available.

Key SSVC decision points have not yet been added.

References

Link	Providers
https://git.kernel.org/stable/c/25947cc5b2374cd5bf627fe3141496444260d04f
https://git.kernel.org/stable/c/2dde6377ab2e46bb80cf066c659ef016f3ad7a9b
https://git.kernel.org/stable/c/32e0b925572686399243834ec99e2a9d85c62eae
https://git.kernel.org/stable/c/470264bbec499e276a89a6431144ae58f411ea4d
https://git.kernel.org/stable/c/d3af04a43db86379df7438bf8bade71685b8a239

History

Wed, 27 May 2026 17:30:00 +0000

Type	Values Removed	Values Added
Weaknesses		CWE-398 CWE-400

Wed, 27 May 2026 14:15:00 +0000

Type	Values Removed	Values Added
Description		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.
Title		ext2: reject inodes with zero i_nlink and valid mode in ext2_iget()
First Time appeared		Linux Linux linux Kernel
CPEs		cpe:2.3:o:linux:linux_kernel::::::::
Vendors & Products		Linux Linux linux Kernel
References		https://git.kernel.org/stable/c/25947cc5b2374cd5bf627fe3141496444260d04f https://git.kernel.org/stable/c/2dde6377ab2e46bb80cf066c659ef016f3ad7a9b https://git.kernel.org/stable/c/32e0b925572686399243834ec99e2a9d85c62eae https://git.kernel.org/stable/c/470264bbec499e276a89a6431144ae58f411ea4d https://git.kernel.org/stable/c/d3af04a43db86379df7438bf8bade71685b8a239

Subscriptions

Linux Linux Kernel

MITRE

Status: PUBLISHED

Assigner: Linux

Published: 2026-05-27T12:55:57.898Z

Updated: 2026-05-27T12:55:57.898Z

Reserved: 2026-05-13T15:03:33.091Z

Link: CVE-2026-46002

Vulnrichment

No data.

NVD

Status : Awaiting Analysis

Published: 2026-05-27T14:17:17.880

Modified: 2026-05-27T14:48:03.013

Link: CVE-2026-46002

Redhat

No data.

OpenCVE Enrichment

Updated: 2026-05-27T17:15:38Z

Weaknesses

Impact

Affected Systems

Risk and Exploitability

Tracking

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