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Linux KernelOperating system · Linux

CVE-2023-53111

HIGH · 7.8 CVSS v3.1 Published 2025-05-02
Fix available
A fix is available. Upgrade to 5.15.104 / 6.1.21 or later.
See remediation →
80/100
Remediation priority · High
Zero-click Patch available

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 · unedited
In the Linux kernel, the following vulnerability has been resolved: loop: Fix use-after-free issues do_req_filebacked() calls blk_mq_complete_request() synchronously or asynchronously when using asynchronous I/O unless memory allocation fails. Hence, modify loop_handle_cmd() such that it does not dereference 'cmd' nor 'rq' after do_req_filebacked() finished unless we are sure that the request has not yet been completed. This patch fixes the following kernel crash: Unable to handle kernel NULL pointer dereference at virtual address 0000000000000054 Call trace: css_put.42938+0x1c/0x1ac loop_process_work+0xc8c/0xfd4 loop_rootcg_workfn+0x24/0x34 process_one_work+0x244/0x558 worker_thread+0x400/0x8fc kthread+0x16c/0x1e0 ret_from_fork+0x10/0x20

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
How this class of weakness works · CWE-416

Memory is used after it has been freed, so its contents — now potentially attacker-controlled — drive the program's behaviour. With careful heap grooming this becomes code execution. The fix requires disciplined ownership of memory and often a targeted rework of the object lifecycle.

General guidance for the use after free class — the official description and references above are authoritative for this specific CVE. Want a bespoke review and a reviewed fix? Ask our team →

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
Affected:>= 4.4, < 5.15.104>= 5.16, < 6.1.21>= 6.2, < 6.2.8= 6.3

CVSS 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

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 · scoped
Upgrade available Upgrade to 5.15.104 / 6.1.21 / 6.2.8 or later
Fixed in 5.15.1046.1.216.2.8
Vendor patch git.kernel.org →
Recommended fix High confidence

Linux kernel >= 5.15.104, >= 6.1.21, >= 6.2.8, or >= 6.4 (depending on which branch you are on)

  1. Identify the current kernel version using 'uname -r'
  2. Determine which stable branch your current kernel version belongs to (4.4-5.15.x, 5.16-6.1.x, 6.2.x, or 6.3)
  3. Upgrade the Linux kernel to a patched version: for 4.4-5.15.x line upgrade to >= 5.15.104, for 5.16-6.1.x line upgrade to >= 6.1.21, for 6.2.x upgrade to >= 6.2.8, for 6.3 upgrade to >= 6.4
  4. Use your distribution's package manager to install the updated kernel (e.g., 'apt-get update && apt-get upgrade' for Debian/Ubuntu, 'yum update' for RHEL/CentOS, or 'dnf update' for Fedora)
  5. Reboot the system to load the new kernel
  6. Verify the new kernel version is running with 'uname -r' and confirm it is one of the fixed versions
Caveat Kernel upgrades may require system reboot and could introduce compatibility issues with custom drivers or modules; test in non-production environment first

Generated from the published advisory — verify against the referenced sources before acting.

We can perform the upgrade in your staging environment and verify nothing breaks — typical engagement from $3,200. Get the upgrade done

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References Go to the primary sourcePrimary sources — vendor advisories, patches and trackers. Where our summary and a reference disagree, the reference wins.

Primary sources

Practitioner notes

Contributed

Peer-ranked notes from engineers who’ve handled CVE-2023-53111 in production — separate from our analysis above.

No notes yet

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What this is

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.

What belongs here
  • 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
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