Vulnerability-Lookup

GHSA-P786-PP8P-8P3M

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

Details

NEMU contains an implementation flaw in its RISC-V Hypervisor CSR handling where henvcfg[7:4] (CBIE/CBCFE/CBZE-related fields) is incorrectly masked/updated based on menvcfg[7:4], so a machine-mode write to menvcfg can implicitly modify the hypervisor's environment configuration. This can lead to incorrect enforcement of virtualization configuration and may cause unexpected traps or denial of service when executing cache-block management instructions in virtualized contexts (V=1).

Severity ?

9.8 (Critical)


                  
                    CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H

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{
  "affected": [],
  "aliases": [
    "CVE-2026-29649"
  ],
  "database_specific": {
    "cwe_ids": [
      "CWE-693"
    ],
    "github_reviewed": false,
    "github_reviewed_at": null,
    "nvd_published_at": "2026-04-20T20:16:48Z",
    "severity": "CRITICAL"
  },
  "details": "NEMU contains an implementation flaw in its RISC-V Hypervisor CSR handling where henvcfg[7:4] (CBIE/CBCFE/CBZE-related fields) is incorrectly masked/updated based on menvcfg[7:4], so a machine-mode write to menvcfg can implicitly modify the hypervisor\u0027s environment configuration. This can lead to incorrect enforcement of virtualization configuration and may cause unexpected traps or denial of service when executing cache-block management instructions in virtualized contexts (V=1).",
  "id": "GHSA-p786-pp8p-8p3m",
  "modified": "2026-04-21T21:31:21Z",
  "published": "2026-04-20T21:31:44Z",
  "references": [
    {
      "type": "ADVISORY",
      "url": "https://nvd.nist.gov/vuln/detail/CVE-2026-29649"
    },
    {
      "type": "WEB",
      "url": "https://github.com/OpenXiangShan/NEMU/issues/681"
    },
    {
      "type": "WEB",
      "url": "https://github.com/OpenXiangShan/NEMU/pull/689"
    },
    {
      "type": "WEB",
      "url": "https://docs.riscv.org/reference/isa/priv/hypervisor.html"
    },
    {
      "type": "WEB",
      "url": "https://docs.riscv.org/reference/isa/priv/machine.html"
    }
  ],
  "schema_version": "1.4.0",
  "severity": [
    {
      "score": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H",
      "type": "CVSS_V3"
    }
  ]
}

CVE-2026-29649 (GCVE-0-2026-29649)

Vulnerability from cvelistv5 – Published: 2026-04-20 00:00 – Updated: 2026-04-21 19:51

Summary

Severity ?

9.8 (Critical)


                        
                          CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H

CWE

Assigner

mitre

References

URL

Tags

	https://github.com/OpenXiangShan/NEMU/issues/681
	https://github.com/OpenXiangShan/NEMU/pull/689
	https://docs.riscv.org/reference/isa/priv/machine.html
	https://docs.riscv.org/reference/isa/priv/hypervi…

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JSON

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{
  "containers": {
    "adp": [
      {
        "metrics": [
          {
            "cvssV3_1": {
              "attackComplexity": "LOW",
              "attackVector": "NETWORK",
              "availabilityImpact": "HIGH",
              "baseScore": 9.8,
              "baseSeverity": "CRITICAL",
              "confidentialityImpact": "HIGH",
              "integrityImpact": "HIGH",
              "privilegesRequired": "NONE",
              "scope": "UNCHANGED",
              "userInteraction": "NONE",
              "vectorString": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H",
              "version": "3.1"
            }
          },
          {
            "other": {
              "content": {
                "id": "CVE-2026-29649",
                "options": [
                  {
                    "Exploitation": "none"
                  },
                  {
                    "Automatable": "yes"
                  },
                  {
                    "Technical Impact": "total"
                  }
                ],
                "role": "CISA Coordinator",
                "timestamp": "2026-04-21T13:47:02.557376Z",
                "version": "2.0.3"
              },
              "type": "ssvc"
            }
          }
        ],
        "problemTypes": [
          {
            "descriptions": [
              {
                "cweId": "CWE-693",
                "description": "CWE-693 Protection Mechanism Failure",
                "lang": "en",
                "type": "CWE"
              }
            ]
          }
        ],
        "providerMetadata": {
          "dateUpdated": "2026-04-21T19:51:00.279Z",
          "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 contains an implementation flaw in its RISC-V Hypervisor CSR handling where henvcfg[7:4] (CBIE/CBCFE/CBZE-related fields) is incorrectly masked/updated based on menvcfg[7:4], so a machine-mode write to menvcfg can implicitly modify the hypervisor\u0027s environment configuration. This can lead to incorrect enforcement of virtualization configuration and may cause unexpected traps or denial of service when executing cache-block management instructions in virtualized contexts (V=1)."
        }
      ],
      "problemTypes": [
        {
          "descriptions": [
            {
              "description": "n/a",
              "lang": "en",
              "type": "text"
            }
          ]
        }
      ],
      "providerMetadata": {
        "dateUpdated": "2026-04-20T19:56:57.812Z",
        "orgId": "8254265b-2729-46b6-b9e3-3dfca2d5bfca",
        "shortName": "mitre"
      },
      "references": [
        {
          "url": "https://github.com/OpenXiangShan/NEMU/issues/681"
        },
        {
          "url": "https://github.com/OpenXiangShan/NEMU/pull/689"
        },
        {
          "url": "https://docs.riscv.org/reference/isa/priv/machine.html"
        },
        {
          "url": "https://docs.riscv.org/reference/isa/priv/hypervisor.html"
        }
      ]
    }
  },
  "cveMetadata": {
    "assignerOrgId": "8254265b-2729-46b6-b9e3-3dfca2d5bfca",
    "assignerShortName": "mitre",
    "cveId": "CVE-2026-29649",
    "datePublished": "2026-04-20T00:00:00.000Z",
    "dateReserved": "2026-03-04T00:00:00.000Z",
    "dateUpdated": "2026-04-21T19:51:00.279Z",
    "state": "PUBLISHED"
  },
  "dataType": "CVE_RECORD",
  "dataVersion": "5.2"
}

Sightings

Author	Source	Type	Date

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.

Detection rules are retrieved from Rulezet.

Action not permitted

GHSA-P786-PP8P-8P3M

CVE-2026-29649 (GCVE-0-2026-29649)

Tags

Sightings

Nomenclature