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Linux KernelOperating system · Linux

CVE-2023-20849

MEDIUM · 6.5 CVSS v3.1 Published 2023-09-04
Mitigation only
No fix yet — a mitigation exists. There is no fixed release. A documented workaround reduces exposure in the meantime.
See remediation →
65/100
Remediation priority · Elevated

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 imgsys_cmdq, there is a possible use after free due to a missing valid range checking. This could lead to local escalation of privilege with System execution privileges needed. User interaction is needed for exploitation. Patch ID: ALPS07340433; Issue ID: ALPS07340350.

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 · moderate confidence

A use-after-free vulnerability in MediaTek's imgsys_cmdq (image system command queue) component due to missing valid range checking. This allows a local attacker with System privileges to potentially escalate to higher privileges through user interaction.

MitigationApply vendor patch ALPS07340433 from MediaTek to address the missing range validation in the imgsys_cmdq driver. Given the System privilege requirement and user interaction needed, prioritize patching on affected devices.

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
Affected:= 6.1
YoctoApplication
Affected:= 4.0
Iot YoctoApplication
Affected:= 23.0
AndroidOperating system
Affected:= 11.0= 12.0

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
High
User interaction
Required
Scope
Unchanged
Confidentiality
High
Integrity
High
Availability
High

CVSS:3.1/AV:L/AC:L/PR:H/UI:R/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. Identify MediaTek hardware platform
    Check /proc/cpuinfo or device tree for MediaTek MTK or MediaTek SoC identifiers. On Android, also check 'getprop ro.hardware' or 'cat /proc/cpuinfo | grep Hardware'
    Affected if The device uses a MediaTek SoC (imgsys_cmdq is MediaTek-specific)
  2. Verify imgsys_cmdq driver presence
    Check if the imgsys_cmdq kernel module or driver is loaded: 'lsmod | grep cmdq' or check /sys/module/ for cmdq modules. Also check 'cat /proc/modules' for cmdq entries
    Affected if The imgsys_cmdq driver is present and loaded on the system
  3. Check Linux kernel version
    Run 'uname -r' or 'cat /proc/version' to obtain the kernel version
    Affected if Kernel version is 6.1.x (specifically version 6.1)
  4. Check Android OS version
    On Android, run 'getprop ro.build.version.release' or check Settings > About Phone > Android version
    Affected if Android version is 11.0 or 12.0
  5. Confirm cmdq driver configuration
    Check driver configuration in /proc/config.gz (if available) or examine module parameters: 'cat /sys/module/cmdq/parameters/*' 2>/dev/null to see if the driver is actively configured
    Affected if The cmdq driver is actively enabled and configured for use

A user is affected if the system runs on MediaTek hardware with the imgsys_cmdq driver loaded, and the OS version matches Android 11.0/12.0 or kernel 6.1, as the vulnerability requires the presence of this specific MediaTek component with System-level access.

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 vendor patch ALPS07340433 from MediaTek to address the missing range validation in the imgsys_cmdq driver. Given the System privilege requirement and user interaction needed, prioritize patching on affected devices.

Recommended fix Moderate confidence

Linux Kernel 6.2+ (upstream) or vendor-specific kernel update containing ALPS07340433

  1. Check if your MediaTek device has received the security patch ALPS07340433 (Android security bulletin)
  2. Contact MediaTek or your device vendor to obtain the specific patch for the imgsys_cmdq driver
  3. Apply the vendor-provided kernel patch that adds valid range checking in the imgsys_cmdq driver
  4. Verify the fix by checking that the kernel no longer exhibits use-after-free behavior in the cmdq subsystem
  5. For Yocto-based systems, apply the vendor-specific CVE fix through the system package manager and rebuild the image
Caveat Vendor-specific patch; may require device-specific testing. Upstream kernel upgrade may introduce driver compatibility changes.

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

Fix this in Linux Kernel Scoped from the published advisory
  • Consultation2.0 h
  • Implementation4.0 h
  • Testing6.0 h
  • Review / QA2.0 h
14.0 hours of engineering $2,380
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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-2023-20849 in production — separate from our analysis above.

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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
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  • Version or environment caveats, and links to real fixes
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