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AndroidOperating system · Google

CVE-2023-21263

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 OSMMapPMRGeneric of pmr_os.c, there is a possible out of bounds write due to an uncaught exception. 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 critical out-of-bounds write vulnerability exists in the Linux kernel's OSMMapPMRGeneric function in pmr_os.c. The flaw stems from an uncaught exception that allows writing beyond allocated memory boundaries, enabling a local attacker to escalate privileges to kernel level without requiring any additional execution privileges or user interaction.

MitigationApply the kernel security patch for CVE-2023-21263 which adds proper exception handling and bounds checking in the pmr_os.c file. Prioritize patching on systems with untrusted local users.

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. Confirm the system is an Android device
    Run 'getprop ro.build.id' or check for /system/build.prop to verify this is an Android system
    Affected if The system is not Android (the CVE only affects Android)
  2. Check the Android security patch level
    Run 'getprop ro.build.version.security_patch' to retrieve the date of the last security update
    Affected if The security patch level is earlier than June 2023 (the month CVE-2023-21263 was fixed) or the property returns empty/unknown, indicating the patch has not been applied
  3. Check the kernel version directly
    Run 'uname -r' or read /proc/version to obtain the running kernel version string
    Affected if The kernel version is older than the patched kernel for your specific Android release and the patch level check is inconclusive
  4. Verify the PMR driver is in use
    Check if /sys/devices/system/memory/ or /dev/mem exists and the device has memory management hardware that uses OSMMapPMRGeneric (this is typically hardware-dependent)
    Affected if The device uses Power Management RAM (PMR) functionality and the kernel has not been patched for this specific vulnerability

A user is affected if they are on an Android device where the kernel security patch for CVE-2023-21263 (June 2023 or later) has not been applied, as indicated by a security patch level earlier than the fix date or an unpatched kernel version.

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 kernel security patch for CVE-2023-21263 which adds proper exception handling and bounds checking in the pmr_os.c file. Prioritize patching on systems with untrusted local users.

Recommended fix High confidence

Android Security Patch Level containing the CVE-2023-21263 fix (typically included in post-June 2023 Android security updates)

  1. 1. Check your Android device for available system updates and apply the latest Android Security Patch Level (SPL) update
  2. 2. If your device manufacturer has released a kernel update addressing CVE-2023-21263, install that update
  3. 3. For enterprise/managed devices, ensure mobile device management (MDM) policies enforce automatic security updates
  4. 4. Verify the fix by confirming your device runs the patched kernel version containing the OSMMapPMRGeneric fix in pmr_os.c
Caveat Kernel updates may have compatibility implications with custom ROMs or modified bootloaders; ensure backup before applying updates

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

Fix this in Android Scoped from the published advisory
  • Consultation6.0 h
  • Implementation12.0 h
  • Testing10.0 h
  • Review / QA6.0 h
34.0 hours of engineering $5,940
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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-2023-21263 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