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

Vulnerability from cvelistv5 – Published: 2026-04-20 00:00 – Updated: 2026-04-21 19:51
VLAI?
Summary
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
CWE
  • n/a
Assigner
References
Show details on NVD website
To clipboard 

{
  "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",
  "vulnerability-lookup:meta": {
    "epss": {
      "cve": "CVE-2026-29649",
      "date": "2026-04-22",
      "epss": "0.00019",
      "percentile": "0.05158"
    },
    "nvd": "{\"cve\":{\"id\":\"CVE-2026-29649\",\"sourceIdentifier\":\"cve@mitre.org\",\"published\":\"2026-04-20T20:16:48.410\",\"lastModified\":\"2026-04-21T20:16:41.027\",\"vulnStatus\":\"Awaiting Analysis\",\"cveTags\":[],\"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).\"}],\"metrics\":{\"cvssMetricV31\":[{\"source\":\"134c704f-9b21-4f2e-91b3-4a467353bcc0\",\"type\":\"Secondary\",\"cvssData\":{\"version\":\"3.1\",\"vectorString\":\"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H\",\"baseScore\":9.8,\"baseSeverity\":\"CRITICAL\",\"attackVector\":\"NETWORK\",\"attackComplexity\":\"LOW\",\"privilegesRequired\":\"NONE\",\"userInteraction\":\"NONE\",\"scope\":\"UNCHANGED\",\"confidentialityImpact\":\"HIGH\",\"integrityImpact\":\"HIGH\",\"availabilityImpact\":\"HIGH\"},\"exploitabilityScore\":3.9,\"impactScore\":5.9}]},\"weaknesses\":[{\"source\":\"134c704f-9b21-4f2e-91b3-4a467353bcc0\",\"type\":\"Secondary\",\"description\":[{\"lang\":\"en\",\"value\":\"CWE-693\"}]}],\"references\":[{\"url\":\"https://docs.riscv.org/reference/isa/priv/hypervisor.html\",\"source\":\"cve@mitre.org\"},{\"url\":\"https://docs.riscv.org/reference/isa/priv/machine.html\",\"source\":\"cve@mitre.org\"},{\"url\":\"https://github.com/OpenXiangShan/NEMU/issues/681\",\"source\":\"cve@mitre.org\"},{\"url\":\"https://github.com/OpenXiangShan/NEMU/pull/689\",\"source\":\"cve@mitre.org\"}]}}",
    "vulnrichment": {
      "containers": "{\"cna\": {\"affected\": [{\"vendor\": \"n/a\", \"product\": \"n/a\", \"versions\": [{\"status\": \"affected\", \"version\": \"n/a\"}]}], \"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\"}], \"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\": [{\"lang\": \"en\", \"type\": \"text\", \"description\": \"n/a\"}]}], \"providerMetadata\": {\"orgId\": \"8254265b-2729-46b6-b9e3-3dfca2d5bfca\", \"shortName\": \"mitre\", \"dateUpdated\": \"2026-04-20T19:56:57.812Z\"}}, \"adp\": [{\"title\": \"CISA ADP Vulnrichment\", \"metrics\": [{\"cvssV3_1\": {\"scope\": \"UNCHANGED\", \"version\": \"3.1\", \"baseScore\": 9.8, \"attackVector\": \"NETWORK\", \"baseSeverity\": \"CRITICAL\", \"vectorString\": \"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H\", \"integrityImpact\": \"HIGH\", \"userInteraction\": \"NONE\", \"attackComplexity\": \"LOW\", \"availabilityImpact\": \"HIGH\", \"privilegesRequired\": \"NONE\", \"confidentialityImpact\": \"HIGH\"}}, {\"other\": {\"type\": \"ssvc\", \"content\": {\"id\": \"CVE-2026-29649\", \"role\": \"CISA Coordinator\", \"options\": [{\"Exploitation\": \"none\"}, {\"Automatable\": \"yes\"}, {\"Technical Impact\": \"total\"}], \"version\": \"2.0.3\", \"timestamp\": \"2026-04-21T13:47:02.557376Z\"}}}], \"problemTypes\": [{\"descriptions\": [{\"lang\": \"en\", \"type\": \"CWE\", \"cweId\": \"CWE-693\", \"description\": \"CWE-693 Protection Mechanism Failure\"}]}], \"providerMetadata\": {\"shortName\": \"CISA-ADP\", \"orgId\": \"134c704f-9b21-4f2e-91b3-4a467353bcc0\", \"dateUpdated\": \"2026-04-21T13:49:49.167Z\"}}]}",
      "cveMetadata": "{\"cveId\": \"CVE-2026-29649\", \"state\": \"PUBLISHED\", \"dateUpdated\": \"2026-04-20T19:56:57.812Z\", \"dateReserved\": \"2026-03-04T00:00:00.000Z\", \"assignerOrgId\": \"8254265b-2729-46b6-b9e3-3dfca2d5bfca\", \"datePublished\": \"2026-04-20T00:00:00.000Z\", \"assignerShortName\": \"mitre\"}",
      "dataType": "CVE_RECORD",
      "dataVersion": "5.2"
    }
  }
}


Log in or create an account to share your comment.




Tags
Taxonomy of the tags.




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.