Privilege escalation via mishandled GPU memory aliases
Published May 10, 2021 · Updated Oct 21, 2025
Use-after-free in Arm Mali drivers through Bifrost r28p0, Valhall r28p0, and Midgard r30p0 allows local users to gain privileges or disclose memory. An evictable GPU allocation retains an alias that can be mapped after the underlying physical pages enter an unsafe lifetime state. The public proof of concept requires access to the Mali device and demonstrates read-only memory disclosure; Arm also reports privilege escalation.
Summary
What happened
Use-after-free in Arm Mali drivers through Bifrost r28p0, Valhall r28p0, and Midgard r30p0 allows local users to gain privileges or disclose memory. An evictable GPU allocation retains an alias that can be mapped after the underlying physical pages enter an unsafe lifetime state. The public proof of concept requires access to the Mali device and demonstrates read-only memory disclosure; Arm also reports privilege escalation.
The record
- CVE
- CVE-2021-28663
- Published
- May 10, 2021
- Updated
- Oct 21, 2025
- Vendor
- Arm
- Product
- Valhall GPU Kernel Driver
- Classifications
- CWE-416, T1068
- Attack vector
- local
- Privileges
- Unavailable
Timeline
How it unfolded
- May 10, 2021CVE publishedPublication date reported by the CVE source.
- Nov 3, 2021Exploitation reportedCISA Known Exploited Vulnerabilities Catalog listing
- Oct 21, 2025Record updatedLatest update available in the CVE record.
Exploitability
Present is not the same as exploitable
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Is a vulnerable build present?
Compare these published version ranges with your installed build and any vendor patches.
- Affected versionversion=0 <=r28p0
What conditions does exploitation require?
What is affected?
Attacks
What attackers are doing with it
Daily unique IPs observed by Shadowserver honeypots for known exploited vulnerabilities (KEVs). Missing observations do not establish an absence of attacks.
Public exploit references
- CVE-2021-28663 basic memory-leak proof of conceptproof of concept · demonstrated
Labels summarize the accepted research assessment. They do not indicate a test against your environment.
Reported exploitation
- CISA Known Exploited Vulnerabilities Catalog listingknown exploited catalog
Technologies
Your stack
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Your stack
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