GHSA-PRQQ-QRC5-XVPR

Vulnerability from github – Published: 2026-04-20 21:31 – Updated: 2026-04-21 21:31
VLAI?
Details

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.

Severity ?
7.5 (High)
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
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{
  "affected": [],
  "aliases": [
    "CVE-2026-29645"
  ],
  "database_specific": {
    "cwe_ids": [
      "CWE-131"
    ],
    "github_reviewed": false,
    "github_reviewed_at": null,
    "nvd_published_at": "2026-04-20T20:16:48Z",
    "severity": "HIGH"
  },
  "details": "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": "GHSA-prqq-qrc5-xvpr",
  "modified": "2026-04-21T21:31:20Z",
  "published": "2026-04-20T21:31:44Z",
  "references": [
    {
      "type": "ADVISORY",
      "url": "https://nvd.nist.gov/vuln/detail/CVE-2026-29645"
    },
    {
      "type": "WEB",
      "url": "https://github.com/OpenXiangShan/NEMU/issues/952"
    },
    {
      "type": "WEB",
      "url": "https://github.com/OpenXiangShan/NEMU/pull/958"
    },
    {
      "type": "WEB",
      "url": "https://github.com/OpenXiangShan/NEMU/commit/481de637d5fc5838356caee80a79e56a33754039"
    },
    {
      "type": "WEB",
      "url": "https://docs.riscv.org/reference/isa/unpriv/v-st-ext.html"
    }
  ],
  "schema_version": "1.4.0",
  "severity": [
    {
      "score": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H",
      "type": "CVSS_V3"
    }
  ]
}


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