CVE-2026-29645

NEMU (OpenXiangShan/NEMU) before v2025.12.r2 contains an improper instruction-validation flaw in its RISC-V Vector (RVV) decoder. The decoder does not correctly validate the funct3 field when decoding vsetvli/vsetivli/vsetvl, allowing certain invalid OP-V instruction encodings to be misinterpreted and executed as vset* configuration instructions rather than raising an illegal-instruction exception. This can be exploited by providing crafted RISC-V binaries to cause incorrect trap behavior, architectural state corruption/divergence, and potential denial of service in systems that rely on NEMU for correct execution or sandboxing.

CVSS v3 7.5 HIGH

7.5^/10

CVSS v3 : HIGH

Vector :

Exploitability : 3.9 / Impact : 3.6

Attack Vector NETWORK

Attack Complexity LOW

Privileges Required NONE

User Interaction NONE

Confidentiality Impact NONE

Integrity Impact NONE

Availability Impact HIGH

Scope UNCHANGED

References

Link	Resource
https://docs.riscv.org/reference/isa/unpriv/v-st-ext.html	Product
https://github.com/OpenXiangShan/NEMU/commit/481de637d5fc5838356caee80a79e56a33754039	Patch
https://github.com/OpenXiangShan/NEMU/issues/952	Issue Tracking
https://github.com/OpenXiangShan/NEMU/pull/958	Issue Tracking

Configurations

Configuration 1 (hide)

cpe:2.3:a:xiangshan:nemu:2025.12:r1:*:*:*:*:*:*

History

No history.

Information

Published : 2026-04-20 20:16

Updated : 2026-06-17 10:29

NVD link : CVE-2026-29645

Mitre link : CVE-2026-29645

CVE.ORG link : CVE-2026-29645

JSON object : View

Products Affected

xiangshan

nemu

CWE

CWE-131

Incorrect Calculation of Buffer Size

CWE-1287

Improper Validation of Specified Type of Input

{"id": "CVE-2026-29645", "cveTags": [], "metrics": {"ssvcV203": [{"source": "134c704f-9b21-4f2e-91b3-4a467353bcc0", "ssvcData": {"id": "CVE-2026-29645", "role": "CISA Coordinator", "options": [{"exploitation": "none"}, {"automatable": "yes"}, {"technicalImpact": "partial"}], "version": "2.0.3", "timestamp": "2026-04-21T13:33:07.838848Z"}}], "cvssMetricV31": [{"type": "Secondary", "source": "134c704f-9b21-4f2e-91b3-4a467353bcc0", "cvssData": {"scope": "UNCHANGED", "version": "3.1", "baseScore": 7.5, "attackVector": "NETWORK", "baseSeverity": "HIGH", "vectorString": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H", "integrityImpact": "NONE", "userInteraction": "NONE", "attackComplexity": "LOW", "availabilityImpact": "HIGH", "privilegesRequired": "NONE", "confidentialityImpact": "NONE"}, "impactScore": 3.6, "exploitabilityScore": 3.9}]}, "affected": [{"source": "cve@mitre.org", "affectedData": [{"vendor": "n/a", "product": "n/a", "versions": [{"status": "affected", "version": "n/a"}]}]}], "published": "2026-04-20T20:16:48.303", "references": [{"url": "https://docs.riscv.org/reference/isa/unpriv/v-st-ext.html", "tags": ["Product"], "source": "cve@mitre.org"}, {"url": "https://github.com/OpenXiangShan/NEMU/commit/481de637d5fc5838356caee80a79e56a33754039", "tags": ["Patch"], "source": "cve@mitre.org"}, {"url": "https://github.com/OpenXiangShan/NEMU/issues/952", "tags": ["Issue Tracking"], "source": "cve@mitre.org"}, {"url": "https://github.com/OpenXiangShan/NEMU/pull/958", "tags": ["Issue Tracking"], "source": "cve@mitre.org"}], "vulnStatus": "Analyzed", "weaknesses": [{"type": "Secondary", "source": "134c704f-9b21-4f2e-91b3-4a467353bcc0", "description": [{"lang": "en", "value": "CWE-131"}, {"lang": "en", "value": "CWE-1287"}]}], "descriptions": [{"lang": "en", "value": "NEMU (OpenXiangShan/NEMU) before v2025.12.r2 contains an improper instruction-validation flaw in its RISC-V Vector (RVV) decoder. The decoder does not correctly validate the funct3 field when decoding vsetvli/vsetivli/vsetvl, allowing certain invalid OP-V instruction encodings to be misinterpreted and executed as vset* configuration instructions rather than raising an illegal-instruction exception. This can be exploited by providing crafted RISC-V binaries to cause incorrect trap behavior, architectural state corruption/divergence, and potential denial of service in systems that rely on NEMU for correct execution or sandboxing."}], "lastModified": "2026-06-17T10:29:50.587", "configurations": [{"nodes": [{"negate": false, "cpeMatch": [{"criteria": "cpe:2.3:a:xiangshan:nemu:2025.12:r1:*:*:*:*:*:*", "vulnerable": true, "matchCriteriaId": "8236EBB4-EE38-481D-AA39-97F19681D5FE"}], "operator": "OR"}]}], "sourceIdentifier": "cve@mitre.org"}