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AndroidOperating system · Google

CVE-2021-0947

HIGH · 7.5 CVSS v3.1 Published 2022-08-24
Mitigation only
No fix yet — a mitigation exists. There is no fixed release. A documented workaround reduces exposure in the meantime.
See remediation →
84/100
Remediation priority · High
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
The method PVRSRVBridgeTLDiscoverStreams allocates puiStreamsInt on the heap, fills the contents of the buffer via TLServerDiscoverStreamsKM, and then copies the buffer to userspace. The method TLServerDiscoverStreamsKM may fail for several reasons including invalid sizes. If this method fails the buffer will be left uninitialized and despite the error will still be copied to userspace. Kernel leak of uninitialized heap data with no privs required.Product: AndroidVersions: Android SoCAndroid ID: A-236838960

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

In Android kernel's PVRSRVBridgeTLDiscoverStreams function, a heap buffer (puiStreamsInt) is populated via TLServerDiscoverStreamsKM and copied to userspace. When TLServerDiscoverStreamsKM fails (e.g., due to invalid sizes), the buffer remains uninitialized yet is still copied to userspace, causing a kernel heap memory leak to unprivileged users.

MitigationApply the vendor-supplied Android security patch for CVE-2021-0947; this kernel-level information disclosure requires a code fix in the driver to properly initialize or not copy the buffer on failure.

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
None
Availability
None

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

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 if PowerVR graphics driver is loaded
    Check for the presence of the PVRSRV kernel module or driver. On Android, examine /proc/modules or look for 'pvrsrv' in kernel messages (dmesg). Alternatively, check /sys/module/ for pvrsrv* entries.
    Affected if The PowerVR (PVRSRV) graphics driver module is present on the device
  2. Verify Android security patch level
    Run 'getprop ro.build.version.security_patch' on the device or check Settings > About Phone > Android security patch level. Compare the date against the fix release date for CVE-2021-0947.
    Affected if The security patch level is earlier than the vendor release containing the fix for this CVE
  3. Confirm kernel exposes the vulnerable ioctl
    Identify if applications can access /dev/pvrsrvkm or similar PowerVR device nodes. Check /dev/ for pvrsrv entries and verify read/write permissions (ls -la /dev/pvrsrv*).
    Affected if The PVRSRV device node exists and is accessible to unprivileged users (typical default configuration)
  4. Check kernel source for the vulnerable code pattern
    If kernel source is available, search for the PVRSRVBridgeTLDiscoverStreams function and verify whether the buffer copy on TLServerDiscoverStreamsKM failure was removed or guarded. This requires source code review.
    Affected if The source code still contains the unconditional buffer copy after failure (unpatched state)

A user is affected if the device has the PowerVR graphics driver present, the Android security patch level predates the CVE-2021-0947 fix, and unprivileged users can access the pvrsrvkm device node.

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

Apply the vendor-supplied Android security patch for CVE-2021-0947; this kernel-level information disclosure requires a code fix in the driver to properly initialize or not copy the buffer on failure.

Fix this in Android Scoped from the published advisory
  • Consultation4.0 h
  • Implementation8.0 h
  • Testing6.0 h
  • Review / QA3.0 h
21.0 hours of engineering $3,680
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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-2021-0947 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
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