Userspace access failures via truncated TASK_SIZE
Published May 20, 2024 · Updated May 12, 2026
Incorrect buffer-size calculation in Linux allows local users to trigger userspace access failures on 64-bit RISC-V NOMMU systems. In arch/riscv/include/asm/pgtable.h, the NOMMU TASK_SIZE macro uses a 32-bit limit for 64-bit builds, causing userspace access checks to reject valid addresses above 4 GB. The condition requires physical RAM above 4 GB; consequences are failed user-memory operations and availability loss.
Summary
What happened
Incorrect buffer-size calculation in Linux allows local users to trigger userspace access failures on 64-bit RISC-V NOMMU systems. In arch/riscv/include/asm/pgtable.h, the NOMMU TASK_SIZE macro uses a 32-bit limit for 64-bit builds, causing userspace access checks to reject valid addresses above 4 GB. The condition requires physical RAM above 4 GB; consequences are failed user-memory operations and availability loss.
The record
- CVE
- CVE-2024-35988
- Published
- May 20, 2024
- Updated
- May 12, 2026
- Vendor
- Siemens
- Product
- SIMATIC S7-1500 TM MFP - GNU/Linux subsystem
- Classifications
- CWE-131, T1499
- Attack vector
- local
- Privileges
- authenticated
Timeline
How it unfolded
- May 20, 2024CVE publishedPublication date reported by the CVE source.
- May 12, 2026Record updatedLatest update available in the CVE record.
Exploitability
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- Affected versionversion=0 <*
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Published CVSS scores
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Attacks
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