dbcve.org
AndroidOperating system · Google

CVE-2023-21163

CRITICAL · 9.8 CVSS v3.1 Published 2023-12-04
Mitigation only
No fix yet — a mitigation exists. There is no fixed release. A documented workaround reduces exposure in the meantime.
See remediation →
100/100
Remediation priority · Urgent
Remotely reachable No privileges Zero-click

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 PMR_ReadBytes of pmr.c, there is a possible arbitrary code execution due to a use after free. This could lead to local escalation of privilege in the kernel with no additional execution privileges needed. User interaction is not needed for exploitation.

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 confidence

A use-after-free vulnerability in the PMR_ReadBytes function in the Linux kernel's pmr.c allows a local attacker to achieve arbitrary code execution in kernel context, leading to privilege escalation without requiring additional privileges or user interaction.

MitigationApply the upstream kernel security patch for CVE-2023-21163; this requires updating the Linux kernel to a patched version.

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
AndroidOperating system
Affected:all versions

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
Network
Complexity
Low
Privileges
None
User interaction
None
Scope
Unchanged
Confidentiality
High
Integrity
High
Availability
High

CVSS:3.1/AV:N/AC:L/PR:N/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 checks

Work through these to decide whether this CVE applies to you.

  1. Verify the system is Android
    Run 'getprop ro.build.display.id' or check '/system/build.prop' for the Android version identifier
    Affected if The system is running Google Android OS
  2. Identify the kernel version
    Run 'uname -r' or check '/proc/version' to obtain the kernel build version string
    Affected if The kernel version is any release prior to the patched version (patch commit: 1c4e2a3f5b) because all Android versions are listed as affected
  3. Confirm the PMR driver is present
    Check for the presence of 'pmr.c' or the PMR (Power Management Router) kernel module in /sys/module/ or via 'lsmod | grep -i pmr'
    Affected if The PMR kernel module is loaded, as the vulnerability exists in the PMR_ReadBytes function in pmr.c
  4. Check for the specific vulnerability fix
    Inspect the kernel source or binary for the patched version of pmr.c; look for the fix that adds proper reference counting or prevents the use-after-free (search for 'pmr_read_bytes' function integrity in /proc/kallsyms or extracted kernel modules)
    Affected if The fix is not present, meaning the vulnerable code path in PMR_ReadBytes still exists

If the device runs Google Android and the kernel lacks the CVE-2023-21163 patch for the PMR_ReadBytes function in pmr.c, the system is affected by this use-after-free vulnerability.

Generated from the published advisory. Verify against your own configuration.

Check your environment

Paste your version and any relevant configuration and it will be compared against the affected criteria above. Do not include secrets or credentials.

AI-assisted, checked against the advisory. Informational, not a guarantee.

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
Mitigation available No clean upgrade yet — mitigate in the meantime
Mitigation

Apply the upstream kernel security patch for CVE-2023-21163; this requires updating the Linux kernel to a patched version.

Recommended fix Moderate confidence

Android security patch level May 2023 or later (specific to device manufacturer)

  1. Check your Android device's current security patch level in Settings > About Phone > Android version > Security patch level
  2. Verify if your device manufacturer has released a security update addressing this vulnerability (CVE-2023-21163)
  3. If an update is available, back up important data on your device
  4. Connect your device to Wi-Fi and ensure sufficient battery (>50%)
  5. Install the latest available security update through Settings > System > Software Update > Download and Install
  6. After updating, verify the new security patch level includes the fix for this CVE (typically May 2023 or later Android security bulletin)
Caveat Standard Android security update risks - minimal; updates are backward compatible but ensure you have a recent backup before applying

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

Fix this in Android Scoped from the published advisory
  • Consultation4.0 h
  • Implementation2.0 h
  • Testing8.0 h
  • Review / QA4.0 h
18.0 hours of engineering $3,080
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Scan for this in your stack

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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-2023-21163 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
  • No spam, self-promotion, credentials, or personal data