Kernel memory access via CSF refcount overflow
Published Nov 7, 2023 · Updated Dec 16, 2025
Use-after-free in Arm Valhall r29p0 through r42p0 and 5th Gen r41p0 through r42p0 drivers allows local users to access freed memory. In the CSF memory-allocation path, an overflowing reference count lets a GPU allocation be released while references remain, leaving stale access to its physical pages. A nonprivileged local account with access to the Mali device node can use crafted GPU memory operations to read or alter kernel memory and interrupt the host.
Summary
What happened
Use-after-free in Arm Valhall r29p0 through r42p0 and 5th Gen r41p0 through r42p0 drivers allows local users to access freed memory. In the CSF memory-allocation path, an overflowing reference count lets a GPU allocation be released while references remain, leaving stale access to its physical pages. A nonprivileged local account with access to the Mali device node can use crafted GPU memory operations to read or alter kernel memory and interrupt the host.
The record
- CVE
- CVE-2023-4295
- Published
- Nov 7, 2023
- Updated
- Dec 16, 2025
- Vendor
- Arm
- Product
- Valhall GPU Kernel Driver
- Classifications
- CWE-190, CWE-416, T1068
- Attack vector
- local
- Privileges
- authenticated
Timeline
How it unfolded
- Nov 7, 2023CVE publishedPublication date reported by the CVE source.
- Dec 16, 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=r29p0 <r43p0 changes=[{"at":"r43p0","status":"unaffected"}]
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.
Weakness, pattern, technique
Public exploit references
No public exploit references are available in this record.
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Technologies
Your stack
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Your stack
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