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Linux KernelOperating system · Linux

CVE-2023-23586

MEDIUM · 5.5 CVSS v3.1 Published 2023-02-17
Fix available
A fix is available. Upgrade to 5.10.161 or later.
See remediation →
57/100
Remediation priority · Elevated
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
Due to a vulnerability in the io_uring subsystem, it is possible to leak kernel memory information to the user process. timens_install calls current_is_single_threaded to determine if the current process is single-threaded, but this call does not consider io_uring's io_worker threads, thus it is possible to insert a time namespace's vvar page to process's memory space via a page fault. When this time namespace is destroyed, the vvar page is also freed, but not removed from the process' memory, and a next page allocated by the kernel will be still available from the user-space process and can leak memory contents via this (read-only) use-after-free vulnerability. We recommend upgrading past version 5.10.161 or commit  788d0824269bef539fe31a785b1517882eafed93 https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/commit/io_uring

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:>= 5.6, < 5.10.161

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
None
Availability
None

CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:N/A:N

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 5.10.161 or later
Fixed in 5.10.161
Vendor patch git.kernel.org →
Recommended fix High confidence

Linux Kernel 5.10.161 or later (or apply commit 788d0824269bef539fe31a785b1517882eafed93 to any supported kernel branch)

  1. 1. Check the current running kernel version with: uname -r
  2. 2. Update your package repository metadata: sudo apt update (Debian/Ubuntu) or sudo yum check-update (RHEL/CentOS)
  3. 3. Install the updated kernel package. On Debian/Ubuntu: sudo apt install linux-image-generic. On RHEL/CentOS: sudo yum install kernel
  4. 4. Verify the available kernel version meets the fix requirement (>= 5.10.161): apt-cache policy linux-image-generic (Debian/Ubuntu) or yum list available kernel (RHEL/CentOS)
  5. 5. If the patched version is not available in default repositories, enable the upstream kernel repository or consider building from source using the commit 788d0824269bef539fe31a785b1517882eafed93
  6. 6. Reboot the system to boot into the new kernel: sudo systemctl reboot
  7. 7. After reboot, verify the running kernel version: uname -r. Confirm it shows 5.10.161 or later
Caveat Kernel upgrades may require driver recompilation or may introduce incompatibilities with custom modules; ensure backups and test in staging 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 $2,850. 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-2023-23586 in production — separate from our analysis above.

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What this is

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What belongs here
  • Verified mitigations, workarounds, and config changes
  • Version or environment caveats, and links to real fixes
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