FKIE_CVE-2026-29645

Vulnerability from fkie_nvd - Published: 2026-04-20 20:16 - Updated: 2026-04-24 19:25
Severity ?
7.5 (High) - CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
Summary
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.
References
cve@mitre.orghttps://docs.riscv.org/reference/isa/unpriv/v-st-ext.htmlProduct
cve@mitre.orghttps://github.com/OpenXiangShan/NEMU/commit/481de637d5fc5838356caee80a79e56a33754039Patch
cve@mitre.orghttps://github.com/OpenXiangShan/NEMU/issues/952Issue Tracking
cve@mitre.orghttps://github.com/OpenXiangShan/NEMU/pull/958Issue Tracking
Impacted products
Vendor Product Version
xiangshan nemu 2025.12
To clipboard 

{
  "configurations": [
    {
      "nodes": [
        {
          "cpeMatch": [
            {
              "criteria": "cpe:2.3:a:xiangshan:nemu:2025.12:r1:*:*:*:*:*:*",
              "matchCriteriaId": "8236EBB4-EE38-481D-AA39-97F19681D5FE",
              "vulnerable": true
            }
          ],
          "negate": false,
          "operator": "OR"
        }
      ]
    }
  ],
  "cveTags": [],
  "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."
    }
  ],
  "id": "CVE-2026-29645",
  "lastModified": "2026-04-24T19:25:35.653",
  "metrics": {
    "cvssMetricV31": [
      {
        "cvssData": {
          "attackComplexity": "LOW",
          "attackVector": "NETWORK",
          "availabilityImpact": "HIGH",
          "baseScore": 7.5,
          "baseSeverity": "HIGH",
          "confidentialityImpact": "NONE",
          "integrityImpact": "NONE",
          "privilegesRequired": "NONE",
          "scope": "UNCHANGED",
          "userInteraction": "NONE",
          "vectorString": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H",
          "version": "3.1"
        },
        "exploitabilityScore": 3.9,
        "impactScore": 3.6,
        "source": "134c704f-9b21-4f2e-91b3-4a467353bcc0",
        "type": "Secondary"
      }
    ]
  },
  "published": "2026-04-20T20:16:48.303",
  "references": [
    {
      "source": "cve@mitre.org",
      "tags": [
        "Product"
      ],
      "url": "https://docs.riscv.org/reference/isa/unpriv/v-st-ext.html"
    },
    {
      "source": "cve@mitre.org",
      "tags": [
        "Patch"
      ],
      "url": "https://github.com/OpenXiangShan/NEMU/commit/481de637d5fc5838356caee80a79e56a33754039"
    },
    {
      "source": "cve@mitre.org",
      "tags": [
        "Issue Tracking"
      ],
      "url": "https://github.com/OpenXiangShan/NEMU/issues/952"
    },
    {
      "source": "cve@mitre.org",
      "tags": [
        "Issue Tracking"
      ],
      "url": "https://github.com/OpenXiangShan/NEMU/pull/958"
    }
  ],
  "sourceIdentifier": "cve@mitre.org",
  "vulnStatus": "Analyzed",
  "weaknesses": [
    {
      "description": [
        {
          "lang": "en",
          "value": "CWE-131"
        },
        {
          "lang": "en",
          "value": "CWE-1287"
        }
      ],
      "source": "134c704f-9b21-4f2e-91b3-4a467353bcc0",
      "type": "Secondary"
    }
  ]
}


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