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Actively exploited in the wild. This CVE is on the CISA Known Exploited Vulnerabilities list — treat remediation as urgent. Federal remediation due by 17 Nov 2021.
Bifrost Gpu Kernel DriverApplication · Arm

CVE-2021-28663

HIGH · 8.8 CVSS v3.1 Published 2021-05-10
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
In the wild Public exploit Remotely reachable 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 Arm Mali GPU kernel driver allows privilege escalation or information disclosure because GPU memory operations are mishandled, leading to a use-after-free. This affects Bifrost r0p0 through r28p0 before r29p0, Valhall r19p0 through r28p0 before r29p0, and Midgard r4p0 through r30p0.

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

Use-after-free vulnerability in Arm Mali GPU kernel driver memory operations allows local privilege escalation to kernel level or information disclosure. The flaw affects GPU memory handling in Bifrost (r0p0-r28p0), Valhall (r19p0-r28p0), and Midgard (r4p0-r30p0) GPU architectures before their respective r29p0 updates.

MitigationUpdate Mali GPU driver to r29p0 or later via vendor-provided firmware/driver updates. For Android devices, apply the latest monthly security patch level that includes the Arm Mali fix.

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
Bifrost Gpu Kernel DriverApplication
Affected:>= r0p0, < r29p0
Midgard Gpu Kernel DriverApplication
Affected:>= r4p0, < r31p0
Valhall Gpu Kernel DriverApplication
Affected:>= r19p0, < r29p0

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
Low
User interaction
None
Scope
Unchanged
Confidentiality
High
Integrity
High
Availability
High

CVSS:3.1/AV:N/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. Check for Arm Mali GPU hardware
    List PCI or platform devices: 'lspci | grep -i mali' or check /sys/bus/platform/devices/ for 'mali' entries
    Affected if No Mali GPU found in the system means not affected
  2. Identify Mali GPU architecture variant
    Check /sys/class/misc/mali0/device/name or 'cat /proc/device-tree/model' on ARM systems to determine if Bifrost, Valhall, or Midgard
    Affected if Architecture must be Bifrost, Valhall, or Midgard to be in scope
  3. Query Mali GPU kernel driver version
    Check /sys/class/misc/mali0/device/driver/version or run 'cat /sys/module/mali*/version' if the module is loaded
    Affected if Unable to determine driver version means further investigation needed
  4. Compare installed version against affected ranges
    Match the driver version to these ranges: Bifrost/Valhall < r29p0 is vulnerable; Midgard < r31p0 is vulnerable
    Affected if Installed version falls within the affected range indicates potential vulnerability
  5. Verify GPU kernel driver is actively loaded
    Run 'lsmod | grep mali' or check 'cat /proc/modules | grep mali' to confirm the driver module is in use
    Affected if Driver not loaded means the attack surface is not present

The system is affected if an Arm Mali GPU (Bifrost, Valhall, or Midgard) is present with a kernel driver version prior to r29p0 (Bifrost/Valhall) or r31p0 (Midgard), and the driver is actively loaded.

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

Update Mali GPU driver to r29p0 or later via vendor-provided firmware/driver updates. For Android devices, apply the latest monthly security patch level that includes the Arm Mali fix.

Recommended fix High confidence

Bifrost: r29p0 or later | Valhall: r29p0 or later | Midgard: r31p0 or later

  1. Identify the specific Arm Mali GPU driver variant in use (Bifrost, Midgard, or Valhall)
  2. Locate the Mali GPU kernel driver package for your system (typically part of the OS or GPU firmware)
  3. Upgrade the Bifrost driver to version r29p0 or later
  4. Upgrade the Valhall driver to version r29p0 or later
  5. Upgrade the Midgard driver to version r31p0 or later
  6. Reboot the system to load the updated driver
  7. Verify the driver version matches the fixed release
Caveat Kernel driver updates typically require system restart and may need coordination with system maintenance windows

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

Fix this in Bifrost Gpu Kernel Driver Exploited in the wild — priority engagement
  • Consultation8.0 h
  • Implementation4.0 h
  • Testing12.0 h
  • Review / QA4.0 h
28.0 hours of engineering $4,840
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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-2021-28663 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
  • 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