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AndroidOperating system · Google

CVE-2017-8246

HIGH · 7.8 CVSS v3.1 Published 2017-05-12
Mitigation only
No fix yet — a mitigation exists. There is no fixed release. A documented workaround reduces exposure in the meantime.
See remediation →
80/100
Remediation priority · High
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 function msm_pcm_playback_close() in all Android releases from CAF using the Linux kernel, prtd is assigned substream->runtime->private_data. Later, prtd is freed. However, prtd is not sanitized and set to NULL, resulting in a dangling pointer. There are other functions that access the same memory (substream->runtime->private_data) with a NULL check, such as msm_pcm_volume_ctl_put(), which means this freed memory could be used.

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 dangling pointer vulnerability exists in the msm_pcm_playback_close() function within the Android Linux kernel audio subsystem. The pointer 'prtd' (assigned from substream->runtime->private_data) is freed but not set to NULL afterward, creating a dangling pointer. Other functions like msm_pcm_volume_ctl_put() access this memory with only a NULL check, resulting in a use-after-free condition where freed memory could be accessed.

MitigationSet substream->runtime->private_data to NULL immediately after freeing prtd in msm_pcm_playback_close() to prevent dangling pointer usage. This ensures all subsequent NULL checks in accessing functions properly handle the freed state.

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
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

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 Android platform usage
    Verify the target system is running Google Android OS (e.g., check /system/build.prop, uname -a shows 'Android' kernel, or device is an Android phone/tablet)
    Affected if System is not running Android - this vulnerability is specific to Android Linux kernel audio subsystem
  2. Identify kernel audio driver
    Check if the kernel includes Qualcomm MSM audio driver by searching for 'msm_pcm' in /proc/kallsyms, kernel modules (lsmod), or kernel config (cat /boot/config* | grep -i msm_pcm)
    Affected if Kernel does not include msm (Qualcomm) audio driver components - the vulnerability exists only in this specific audio subsystem
  3. Locate vulnerable function in kernel
    Search kernel source or System.map for symbol 'msm_pcm_playback_close' using: grep -r 'msm_pcm_playback_close' /proc/kallsyms 2>/dev/null or review kernel source if available
    Affected if Function msm_pcm_playback_close is not present in the kernel - the vulnerability only exists where this function is implemented
  4. Inspect dangling pointer pattern
    If kernel source is accessible, examine the msm_pcm_playback_close() function implementation and verify if substream->runtime->private_data is freed without being set to NULL afterward
    Affected if The code shows prtd (from substream->runtime->private_data) is freed and the pointer is NOT set to NULL - this is the vulnerable condition
  5. Check for NULL validation in accessing functions
    If kernel source is accessible, examine msm_pcm_volume_ctl_put() or similar functions that access the freed pointer - verify they only perform NULL check without additional validation
    Affected if Accessing functions rely solely on NULL checks without verifying the pointer was properly invalidated - this enables use-after-free exploitation

User is affected if running Android with a kernel containing the msm_pcm audio driver where substream->runtime->private_data is freed without being NULL'd in msm_pcm_playback_close().

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.

From vendor data
Mitigation available No clean upgrade yet — mitigate in the meantime
Mitigation

Set substream->runtime->private_data to NULL immediately after freeing prtd in msm_pcm_playback_close() to prevent dangling pointer usage. This ensures all subsequent NULL checks in accessing functions properly handle the freed state.

Fix this in Android Scoped from the published advisory
  • Consultation2.0 h
  • Implementation4.0 h
  • Testing6.0 h
  • Review / QA3.0 h
15.0 hours of engineering $2,560
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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-2017-8246 in production — separate from our analysis above.

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What this is

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