Execution interruption via rejected fence instruction fields
Published Jul 18, 2022 · Updated Aug 3, 2024
Improper instruction handling in OpenHW Group CVA6 allows attackers to interrupt execution through nonstandard fence instructions. The MISC_MEM decoder incorrectly checks reserved rd, rs1, and immediate fields, raising an illegal-instruction exception rather than applying the RISC-V rule that reserved fields are ignored. Exploitation requires local low-privilege code execution; the resulting exception disrupts the affected application without disclosed data exposure or modification.
Summary
What happened
Improper instruction handling in OpenHW Group CVA6 allows attackers to interrupt execution through nonstandard fence instructions. The MISC_MEM decoder incorrectly checks reserved rd, rs1, and immediate fields, raising an illegal-instruction exception rather than applying the RISC-V rule that reserved fields are ignored. Exploitation requires local low-privilege code execution; the resulting exception disrupts the affected application without disclosed data exposure or modification.
The record
- CVE
- CVE-2022-34639
- Published
- Jul 18, 2022
- Updated
- Aug 3, 2024
- Vendor
- Unknown vendor
- Product
- Unknown product
- Classifications
- CWE-755, T1499.004
- Attack vector
- local
- Privileges
- authenticated
Timeline
How it unfolded
- Jul 18, 2022CVE publishedPublication date reported by the CVE source.
- Aug 3, 2024Record updatedLatest update available in the CVE record.
Exploitability
Present is not the same as exploitable
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What conditions does exploitation require?
What is affected?
Affected products and versions are unavailable in this record.
Published CVSS scores
CVSS describes severity. EPSS estimates exploitation probability.
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
- CVA6 nonzero fence-field reproducerproof of concept · demonstrated
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Technologies
Your stack
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Your stack
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