CVE-2026-29645 (GCVE-0-2026-29645)

Vulnerability from cvelistv5 – Published: 2026-04-20 00:00 – Updated: 2026-04-21 19:51
VLAI
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.
Severity
7.5 (High)
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
SSVC
Exploitation: none Automatable: yes Technical Impact: partial
CISA Coordinator · CISA-ADP (v2.0.3)
Decision recorded 2026-04-21 13:33 UTC
CWE
  • n/a
  • CWE-131 - Incorrect Calculation of Buffer Size
  • CWE-1287 - Improper Validation of Specified Type of Input
Assigner
mitre CNA under the mitre root
CNA scorecard E 28/100 over 2325 records in the last 180 days details
References
Show details on NVD website
To clipboard 

{
  "containers": {
    "adp": [
      {
        "metrics": [
          {
            "cvssV3_1": {
              "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"
            }
          },
          {
            "other": {
              "content": {
                "id": "CVE-2026-29645",
                "options": [
                  {
                    "Exploitation": "none"
                  },
                  {
                    "Automatable": "yes"
                  },
                  {
                    "Technical Impact": "partial"
                  }
                ],
                "role": "CISA Coordinator",
                "timestamp": "2026-04-21T13:33:07.838848Z",
                "version": "2.0.3"
              },
              "type": "ssvc"
            }
          }
        ],
        "problemTypes": [
          {
            "descriptions": [
              {
                "cweId": "CWE-131",
                "description": "CWE-131 Incorrect Calculation of Buffer Size",
                "lang": "en",
                "type": "CWE"
              }
            ]
          },
          {
            "descriptions": [
              {
                "cweId": "CWE-1287",
                "description": "CWE-1287 Improper Validation of Specified Type of Input",
                "lang": "en",
                "type": "CWE"
              }
            ]
          }
        ],
        "providerMetadata": {
          "dateUpdated": "2026-04-21T19:51:06.424Z",
          "orgId": "134c704f-9b21-4f2e-91b3-4a467353bcc0",
          "shortName": "CISA-ADP"
        },
        "title": "CISA ADP Vulnrichment"
      }
    ],
    "cna": {
      "affected": [
        {
          "product": "n/a",
          "vendor": "n/a",
          "versions": [
            {
              "status": "affected",
              "version": "n/a"
            }
          ]
        }
      ],
      "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."
        }
      ],
      "problemTypes": [
        {
          "descriptions": [
            {
              "description": "n/a",
              "lang": "en",
              "type": "text"
            }
          ]
        }
      ],
      "providerMetadata": {
        "dateUpdated": "2026-04-20T19:24:42.410Z",
        "orgId": "8254265b-2729-46b6-b9e3-3dfca2d5bfca",
        "shortName": "mitre"
      },
      "references": [
        {
          "url": "https://github.com/OpenXiangShan/NEMU/issues/952"
        },
        {
          "url": "https://github.com/OpenXiangShan/NEMU/pull/958"
        },
        {
          "url": "https://github.com/OpenXiangShan/NEMU/commit/481de637d5fc5838356caee80a79e56a33754039"
        },
        {
          "url": "https://docs.riscv.org/reference/isa/unpriv/v-st-ext.html"
        }
      ]
    }
  },
  "cveMetadata": {
    "assignerOrgId": "8254265b-2729-46b6-b9e3-3dfca2d5bfca",
    "assignerShortName": "mitre",
    "cveId": "CVE-2026-29645",
    "datePublished": "2026-04-20T00:00:00.000Z",
    "dateReserved": "2026-03-04T00:00:00.000Z",
    "dateUpdated": "2026-04-21T19:51:06.424Z",
    "state": "PUBLISHED"
  },
  "dataType": "CVE_RECORD",
  "dataVersion": "5.2",
  "vulnerability-lookup:meta": {
    "epss": {
      "cve": "CVE-2026-29645",
      "date": "2026-10-19",
      "epss": "0.00742",
      "percentile": "0.53858"
    },
    "nvd": {
      "cve": {
        "affected": [
          {
            "affectedData": [
              {
                "product": "n/a",
                "vendor": "n/a",
                "versions": [
                  {
                    "status": "affected",
                    "version": "n/a"
                  }
                ]
              }
            ],
            "source": "cve@mitre.org"
          }
        ],
        "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": "2026-06-17T10:29:50.587",
        "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"
            }
          ],
          "ssvcV203": [
            {
              "source": "134c704f-9b21-4f2e-91b3-4a467353bcc0",
              "ssvcData": {
                "id": "CVE-2026-29645",
                "options": [
                  {
                    "exploitation": "none"
                  },
                  {
                    "automatable": "yes"
                  },
                  {
                    "technicalImpact": "partial"
                  }
                ],
                "role": "CISA Coordinator",
                "timestamp": "2026-04-21T13:33:07.838848Z",
                "version": "2.0.3"
              }
            }
          ]
        },
        "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"
          }
        ]
      }
    },
    "redhat_vex": {
      "current_release_date": "2026-04-21T01:22:23+00:00",
      "cve": "CVE-2026-29645",
      "id": "CVE-2026-29645",
      "initial_release_date": "2026-01-01T00:00:00+00:00",
      "product_status:known_not_affected": "1",
      "source": "Red Hat CSAF VEX",
      "status": "final",
      "title": "CVE-2026-29645",
      "url": "https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-29645.json",
      "version": "3"
    },
    "vulnrichment": {
      "containers": {
        "adp": [
          {
            "metrics": [
              {
                "cvssV3_1": {
                  "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"
                }
              },
              {
                "other": {
                  "content": {
                    "id": "CVE-2026-29645",
                    "options": [
                      {
                        "Exploitation": "none"
                      },
                      {
                        "Automatable": "yes"
                      },
                      {
                        "Technical Impact": "partial"
                      }
                    ],
                    "role": "CISA Coordinator",
                    "timestamp": "2026-04-21T13:33:07.838848Z",
                    "version": "2.0.3"
                  },
                  "type": "ssvc"
                }
              }
            ],
            "problemTypes": [
              {
                "descriptions": [
                  {
                    "cweId": "CWE-131",
                    "description": "CWE-131 Incorrect Calculation of Buffer Size",
                    "lang": "en",
                    "type": "CWE"
                  }
                ]
              },
              {
                "descriptions": [
                  {
                    "cweId": "CWE-1287",
                    "description": "CWE-1287 Improper Validation of Specified Type of Input",
                    "lang": "en",
                    "type": "CWE"
                  }
                ]
              }
            ],
            "providerMetadata": {
              "dateUpdated": "2026-04-21T13:32:16.123Z",
              "orgId": "134c704f-9b21-4f2e-91b3-4a467353bcc0",
              "shortName": "CISA-ADP"
            },
            "title": "CISA ADP Vulnrichment"
          }
        ],
        "cna": {
          "affected": [
            {
              "product": "n/a",
              "vendor": "n/a",
              "versions": [
                {
                  "status": "affected",
                  "version": "n/a"
                }
              ]
            }
          ],
          "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."
            }
          ],
          "problemTypes": [
            {
              "descriptions": [
                {
                  "description": "n/a",
                  "lang": "en",
                  "type": "text"
                }
              ]
            }
          ],
          "providerMetadata": {
            "dateUpdated": "2026-04-20T19:24:42.410Z",
            "orgId": "8254265b-2729-46b6-b9e3-3dfca2d5bfca",
            "shortName": "mitre"
          },
          "references": [
            {
              "url": "https://github.com/OpenXiangShan/NEMU/issues/952"
            },
            {
              "url": "https://github.com/OpenXiangShan/NEMU/pull/958"
            },
            {
              "url": "https://github.com/OpenXiangShan/NEMU/commit/481de637d5fc5838356caee80a79e56a33754039"
            },
            {
              "url": "https://docs.riscv.org/reference/isa/unpriv/v-st-ext.html"
            }
          ]
        }
      },
      "cveMetadata": {
        "assignerOrgId": "8254265b-2729-46b6-b9e3-3dfca2d5bfca",
        "assignerShortName": "mitre",
        "cveId": "CVE-2026-29645",
        "datePublished": "2026-04-20T00:00:00.000Z",
        "dateReserved": "2026-03-04T00:00:00.000Z",
        "dateUpdated": "2026-04-21T19:51:06.424Z",
        "state": "PUBLISHED"
      },
      "dataType": "CVE_RECORD",
      "dataVersion": "5.2"
    }
  }
}



Log in or create an account to share your comment.




Tags
Taxonomy of the tags.




Drag nodes to arrange them. Double-click a related vulnerability to open it, or a source to visit its link. The Physics button on the left tunes the layout and the simulation; the legend at the bottom left hides or shows nodes by kind and by sighting type.

Forecast uses a logistic model when the trend is rising, or an exponential decay model when the trend is falling. Fitted via linearized least squares.

Sightings

Author Source Type Date Other

Nomenclature

  • Seen: The vulnerability was mentioned, discussed, or observed by the user.
  • Confirmed: The vulnerability has been validated from an analyst's perspective.
  • Published Proof of Concept: A public proof of concept is available for this vulnerability.
  • Exploited: The vulnerability was observed as exploited by the user who reported the sighting.
  • Patched: The vulnerability was observed as successfully patched by the user who reported the sighting.
  • Not exploited: The vulnerability was not observed as exploited by the user who reported the sighting.
  • Not confirmed: The user expressed doubt about the validity of the vulnerability.
  • Not patched: The vulnerability was not observed as successfully patched by the user who reported the sighting.
Vulnerability timeline

Sightings and recorded dates, grouped by day · UTC

JSON

Loading timeline…




    Related by attack behaviour

    Vulnerabilities whose description is nearest to this one in the vector space of the CIRCL/vulnerability-attack-technique-biencoder model. This is a similarity search over the bi-encoder space (plain cosine), not a classification, and it has no measured accuracy.