Cross-context IMSIC disclosure via missing CSR checks
Published Apr 20, 2026 · Updated Apr 20, 2026
Improper privilege management in OpenXiangShan NEMU allows remote authenticated users to disclose IMSIC state through stopei and vstopei CSRs. In mode=1, its CSR access path ignores the cleared mstateen0.IMSIC gate and fails to raise the required illegal-instruction exception. This requires lower-privileged code execution and exposes interrupt-controller state across privilege contexts, with no reported ability to modify it or interrupt service.
Summary
What happened
Improper privilege management in OpenXiangShan NEMU allows remote authenticated users to disclose IMSIC state through stopei and vstopei CSRs. In mode=1, its CSR access path ignores the cleared mstateen0.IMSIC gate and fails to raise the required illegal-instruction exception. This requires lower-privileged code execution and exposes interrupt-controller state across privilege contexts, with no reported ability to modify it or interrupt service.
The record
- CVE
- CVE-2026-29647
- Published
- Apr 20, 2026
- Updated
- Apr 20, 2026
- Vendor
- Unknown vendor
- Product
- Unknown product
- Classifications
- CWE-269, T1005
- Attack vector
- network
- Privileges
- authenticated
Timeline
How it unfolded
- Apr 20, 2026CVE publishedPublication date reported by the CVE source.
- Apr 20, 2026Record updatedLatest update available in the CVE record.
Exploitability
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What is affected?
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Published CVSS scores
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Attacks
What attackers are doing with it
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Public exploit references
- IMSIC access reproduction stepsproof of concept · demonstrated
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Technologies
Your stack
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Your stack
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