CVE-2025-40167
ext4: detect invalid INLINE_DATA + EXTENTS flag combination
No known exploitation. EPSS puts it in the 4th percentile. A vendor fix is available.
What to do
The vendor has published a fix. Version details are below where the sources state them.
What it is
From the CVE record
In the Linux kernel, the following vulnerability has been resolved: ext4: detect invalid INLINE_DATA + EXTENTS flag combination syzbot reported a BUG_ON in ext4_es_cache_extent() when opening a verity file on a corrupted ext4 filesystem mounted without a journal. The issue is that the filesystem has an inode with both the INLINE_DATA and EXTENTS flags set: EXT4-fs error (device loop0): ext4_cache_extents:545: inode #15: comm syz.0.17: corrupted extent tree: lblk 0 < prev 66 Investigation revealed that the inode has both flags set: DEBUG: inode 15 - flag=1, i_inline_off=164, has_inline=1, extents_flag=1 This is an invalid combination since an inode should have either: - INLINE_DATA: data stored directly in the inode - EXTENTS: data stored in extent-mapped blocks Having both flags causes ext4_has_inline_data() to return true, skipping extent tree validation in __ext4_iget(). The unvalidated out-of-order extents then trigger a BUG_ON in ext4_es_cache_extent() due to integer underflow when calculating hole sizes. Fix this by detecting this invalid flag combination early in ext4_iget() and rejecting the corrupted inode.
In plain language
No plain-language summary for this CVE yet.
Exploitation
Where each signal puts this CVE on the scale from published to confirmed exploited.
- CISA KEV
Not in the catalog. CISA has not confirmed exploitation.
- Public exploits
No public exploit or proof of concept found in the sources we track.
- EPSS
0.2% chance of exploitation activity in the next 30 days, which ranks it in the 4th percentile of scored CVEs.
Exploit Prediction Scoring System, FIRST.org. A probability, not a confirmation.
Lifecycle
6 events over 260 days, from the signal feeds we watch.
- Patch availablerecord updated
- OpenVAS check added
- Patch availablepublished, record updated
Affected products
Technical detail
CVSS 3.1 vector
Open in the CVSS calculatorCVSS:3.1/AV:L/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H
Scored 7.8 by NVD.
How it is reached
- Attack Vector LocalRequires local access to the vulnerable system (e.g. local login, malicious file)
- Attack Complexity LowNo special conditions — the attack can be reliably reproduced
- Privileges Required NoneNo authentication required — anyone can exploit this
- User Interaction RequiredA user must click a link, open a file, or perform some action
Scope
- Scope UnchangedImpact is limited to the vulnerable component itself
Impact if exploited
- Confidentiality HighTotal information disclosure — all data in the component is compromised
- Integrity HighTotal loss of integrity — attacker can modify any data in the component
- Availability HighTotal denial of service — the component is completely unavailable
Sources
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