CVE-2021-0606
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 · uneditedIn drm_syncobj_handle_to_fd of drm_syncobj.c, there is a possible use after free due to incorrect refcounting. This could lead to local escalation of privilege with System execution privileges needed. User interaction is not needed for exploitation.Product: AndroidVersions: Android kernelAndroid ID: A-168034487
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 confidenceUse-after-free vulnerability in the drm_syncobj_handle_to_fd function within the Linux kernel's Direct Rendering Manager (DRM) subsystem. The issue stems from incorrect reference counting logic when handling syncobj file descriptors, leading to a memory safety flaw that can be exploited for local privilege escalation.
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 dataall versionsCVSS 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
- None
- Scope
- Unchanged
- Confidentiality
- High
- Integrity
- High
- Availability
- High
CVSS:3.1/AV:L/AC:L/PR:H/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 checksWork through these to decide whether this CVE applies to you.
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Confirm the operating system is AndroidRun 'getprop ro.build.version.release' or check /system/build.prop to verify the OS is Google AndroidAffected if The system is not running Google Android (this CVE affects Android exclusively)
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Verify the Linux kernel has DRM subsystem supportCheck for the presence of DRM modules or check kernel config for CONFIG_DRM (typically found in /boot/config-$(uname -r) or /proc/config.gz)Affected if The kernel does not have DRM support compiled in (the vulnerable code resides in the DRM subsystem)
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Check if drm_syncobj module is available or loadedLook for drm_syncobj in /proc/modules, or check kernel config for CONFIG_DRM_SYNCOBJ, or examine /sys/module/drm_syncobj 2>/dev/nullAffected if The drm_syncobj module is not present (the vulnerability is in the drm_syncobj_handle_to_fd function specifically)
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Identify the kernel versionRun 'uname -r' or check /proc/version to obtain the running kernel versionAffected if The kernel version has not received the CVE-2021-0606 patch (the flaw exists in unpatched kernel versions)
A user is affected if running Google Android with a Linux kernel that includes the DRM syncobj functionality (drm_syncobj module) and has not been patched for CVE-2021-0606.
Generated from the published advisory. Verify against your own configuration.
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 dataApply the vendor-provided kernel patch that corrects the reference counting in drm_syncobj.c; this is a kernel-level fix requiring a system update or custom kernel rebuild.
- Consultation4.0 h
- Implementation6.0 h
- Testing12.0 h
- Review / QA6.0 h
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Scan for this in your stack
Free · runs locallyCheck whether your project pulls in CVE-2021-0606 — or any other known-vulnerable package — straight from your lock files. Free and open source; it runs locally and uploads nothing.
References Go to the primary sourcePrimary sources — vendor advisories, patches and trackers. Where our summary and a reference disagree, the reference wins.
Primary sourcesPractitioner notes
ContributedPeer-ranked notes from engineers who’ve handled CVE-2021-0606 in production — separate from our analysis above.
The advisory tells you what broke. It rarely tells you what actually worked. If you’ve dealt with this one, that detail is what the next engineer is searching for.
- The version that genuinely resolved it — not the one the vendor claimed
- A config change or rule that shut the vector down
- A gotcha in the upgrade path that cost you an afternoon
No notes yet
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- Verified mitigations, workarounds, and config changes
- Version or environment caveats, and links to real fixes
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