Kernel panic via zero-value runtime fixup
Published Jul 25, 2025 · Updated May 11, 2026
NULL pointer dereference in Linux 6.15 through 6.15.4 allows local users to cause a kernel panic during RISC-V NOMMU runtime patching. The __runtime_fixup_32 function handles a zero upper 32-bit address by patching both instructions to NOPs, leaving garbage in the destination register. An affected RISC-V NOMMU build and a physical address below 4 GiB are required; dereferencing the malformed pointer crashes the kernel.
Summary
What happened
NULL pointer dereference in Linux 6.15 through 6.15.4 allows local users to cause a kernel panic during RISC-V NOMMU runtime patching. The __runtime_fixup_32 function handles a zero upper 32-bit address by patching both instructions to NOPs, leaving garbage in the destination register. An affected RISC-V NOMMU build and a physical address below 4 GiB are required; dereferencing the malformed pointer crashes the kernel.
The record
- CVE
- CVE-2025-38433
- Published
- Jul 25, 2025
- Updated
- May 11, 2026
- Vendor
- The Linux Kernel Organization
- Product
- Linux
- Classifications
- CWE-476
- Attack vector
- local
- Privileges
- authenticated
Timeline
How it unfolded
- Jul 25, 2025CVE publishedPublication date reported by the CVE source.
- May 11, 2026Record 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=6.15
- Affected versionversion=a44fb5722199de8338d991db5ad3d509192179bb <0a24b00dcde83934a3cc13e4c6b775522903496b
- Affected versionversion=a44fb5722199de8338d991db5ad3d509192179bb <8d90d9872edae7e78c3a12b98e239bfaa66f3639
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What is affected?
Published CVSS scores
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Attacks
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Technologies
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