Linux KernelOperating system · Linux
CVE-2023-1252
Official description Straight from the sourceThe vendor's or NVD's own wording, published unedited. Authoritative, but often terse — it says what broke, rarely what to do.
NVD · uneditedA use-after-free flaw was found in the Linux kernel’s Ext4 File System in how a user triggers several file operations simultaneously with the overlay FS usage. This flaw allows a local user to crash or potentially escalate their privileges on the system. Only if patch 9a2544037600 ("ovl: fix use after free in struct ovl_aio_req") not applied yet, the kernel could be affected.
Technical summary Written by usOur analysis, written from the advisory, the CVSS vector and the affected-version data. It adds context the advisory leaves out, and never invents facts that are not in the source.
dbcve analysis · high confidenceA use-after-free vulnerability exists in the Linux kernel's Ext4 file system when used in conjunction with overlay FS. By triggering multiple file operations simultaneously, a local attacker can exploit a race condition leading to use-after-free of the ovl_aio_req structure, potentially achieving privilege escalation.
Verify against the referenced sources before acting — the references below are authoritative for this CVE, this summary is not.
Affected products & versions What the vendor confirmedThe version ranges the vendor confirmed as vulnerable. If your version sits inside a range here, treat yourself as exposed until you have upgraded.
NVD · CPE data
Linux KernelOperating system
>= 5.6, < 5.10.80>= 5.11, < 5.14.19>= 5.15, < 5.15.3CVSS breakdown How the score is builtThe industry scoring standard. It rates how the flaw is reached, what it takes to exploit, and what an attacker gains — the score is derived from those, not the other way round.
From the vector- Attack vector
- Local
- Complexity
- Low
- Privileges
- Low
- User interaction
- None
- Scope
- Unchanged
- Confidentiality
- High
- Integrity
- High
- Availability
- High
CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
Am I affected? How to checkSteps we derive from the advisory and the affected-version data, so you can decide whether this CVE reaches your setup. They are a guide, not a scan — your own configuration is the authority.
dbcve checksWork through these to decide whether this CVE applies to you.
-
Check kernel versionRun 'uname -r' to get the running kernel version, then compare it to the affected ranges: >= 5.6 and < 5.10.80, >= 5.11 and < 5.14.19, >= 5.15 and < 5.15.3Affected if The installed kernel version falls within any of the three affected ranges
-
Verify overlay filesystem is in useRun 'mount | grep -i overlay' to see if any overlay filesystems are mountedAffected if No overlay filesystems are mounted - the vulnerability requires overlay FS to be active
-
Confirm ext4 is accessed through or under overlayRun 'mount | grep -E "overlay|ext4"' to identify if ext4 is either the lower layer of an overlay mount or if ext4 is accessed within an overlay directory structureAffected if ext4 filesystem content is being accessed through an overlay mount point, creating the vulnerable combination
-
Check for active AIO operationsInspect running processes using AIO by checking /proc/*/fd for io_uring or aio context, or monitor with 'strace -f -e io_submit' on suspected workloadsAffected if Applications are performing asynchronous I/O operations (io_submit, io_uring) on files within the overlay+ext4 combination, which triggers the race condition
A system is affected if it runs a kernel version within the specified ranges AND has overlay FS mounted with ext4 as the lower layer or accessed content, AND there are active AIO operations occurring on those files.
Generated from the published advisory. Verify against your own configuration.
Remediation Closing itWhat it takes to close this. Where a vendor fix exists we point at it; where none exists we say so plainly, and can build one. Effort estimates are scoped from the advisory, not from your codebase.
dbcve · scoped5.10.805.14.195.15.3
Apply kernel patch 9a2544037600 ('ovl: fix use after free in struct ovl_aio_req') or update to a kernel version containing this fix.
Kernel 5.10.80 (or later 5.10.x), 5.14.19 (or later 5.14.x), or 5.15.3 (or later 5.15.x)
- Identify the current running kernel version using 'uname -r'
- Determine which kernel branch you are on (5.10.x, 5.14.x, or 5.15.x)
- For 5.6+ to 5.10.x systems: upgrade kernel to version 5.10.80 or later
- For 5.11+ to 5.14.x systems: upgrade kernel to version 5.14.19 or later
- For 5.15+ to 5.15.2 systems: upgrade kernel to version 5.15.3 or later
- Reboot the system into the new kernel
- Verify the fix is applied by checking the kernel version matches or exceeds the fixed release
Generated from the published advisory — verify against the referenced sources before acting.
Fix this in Linux Kernel
Scoped from the published advisory
- Consultation4.0 h
- Implementation8.0 h
- Testing4.0 h
- Review / QA2.0 h
An estimate, not a bill — we confirm scope with you before any work starts. Need it this week? Rush from $5,120.
Scan for this in your stack
Free · runs locallyCheck whether your project pulls in CVE-2023-1252 — or any other known-vulnerable package — straight from your lock files. Free and open source; it runs locally and uploads nothing.
References Go to the primary sourcePrimary sources — vendor advisories, patches and trackers. Where our summary and a reference disagree, the reference wins.
Primary sourcesPractitioner notes
ContributedPeer-ranked notes from engineers who’ve handled CVE-2023-1252 in production — separate from our analysis above.
The advisory tells you what broke. It rarely tells you what actually worked. If you’ve dealt with this one, that detail is what the next engineer is searching for.
- The version that genuinely resolved it — not the one the vendor claimed
- A config change or rule that shut the vector down
- A gotcha in the upgrade path that cost you an afternoon
No notes yet
Be the first to add a field note for this CVE — a mitigation you’ve verified, a version caveat, or a link to a working fix. Sign in above to contribute.
A place for practitioners to share what actually worked: a mitigation you’ve tested, a configuration change, a version- or environment-specific caveat, or a link to a verified patch. The most useful notes rise to the top as peers upvote them, so the signal stays high.
- Verified mitigations, workarounds, and config changes
- Version or environment caveats, and links to real fixes
- No weaponised exploit code, or anything meant to cause harm
- No spam, self-promotion, credentials, or personal data