CVE-2026-72705

Full vulnerability record from the local CVENow database.

Description

The guard checker in Rocq Prover does not follow recursive calls made through a fixpoint's own arguments. A fixpoint may pass itself as a higher-order argument to a second fixpoint, which then applies it to a value that is not a subterm of the structural argument. Passing the recursive function to a plain definition is rejected because the checker unfolds the definition and observes the call, but passing it to a fixpoint is accepted because higher-order recursive calls through fixpoint arguments are not tracked. This admits a type that is definitionally equal to its own negation, so self-application produces False in purely definitional code, without tactics, axioms, plugins or unsafe flags, and Print Assumptions reports the result as closed under the global context. Fixed in Rocq 9.2.0.

Severity

MEDIUM

CVSS score

6.8 (v4.0)

Vulnerability status

Deferred

Source identifier

[email protected]

Published

2026-08-24 20:17:18.520000

Last modified

2026-10-26 02:17:07.363000

View original CVE JSON

{
  "id": "CVE-2026-72705",
  "sourceIdentifier": "[email protected]",
  "published": "2026-08-24T20:17:18.520",
  "lastModified": "2026-10-26T02:17:07.363",
  "vulnStatus": "Deferred",
  "cveTags": [],
  "descriptions": [
    {
      "lang": "en",
      "value": "The guard checker in Rocq Prover does not follow recursive calls made through a fixpoint's own arguments. A fixpoint may pass itself as a higher-order argument to a second fixpoint, which then applies it to a value that is not a subterm of the structural argument. Passing the recursive function to a plain definition is rejected because the checker unfolds the definition and observes the call, but passing it to a fixpoint is accepted because higher-order recursive calls through fixpoint arguments are not tracked. This admits a type that is definitionally equal to its own negation, so self-application produces False in purely definitional code, without tactics, axioms, plugins or unsafe flags, and Print Assumptions reports the result as closed under the global context. Fixed in Rocq 9.2.0."
    },
    {
      "lang": "es",
      "value": "El verificador de guardas en Rocq Prover no sigue las llamadas recursivas realizadas a través de los propios argumentos de un punto fijo. Un punto fijo puede pasarse a sí mismo como un argumento de orden superior a un segundo punto fijo, el cual luego lo aplica a un valor que no es un subtérmino del argumento estructural. Pasar la función recursiva a una definición simple es rechazado porque el verificador despliega la definición y observa la llamada, pero pasarlo a un punto fijo es aceptado porque las llamadas recursivas de orden superior a través de argumentos de punto fijo no son rastreadas. Esto admite un tipo que es definicionalmente igual a su propia negación, por lo que la autoaplicación produce Falso en código puramente definicional, sin tácticas, axiomas, plugins o flags inseguros, y Print Assumptions informa el resultado como cerrado bajo el contexto global. Corregido en Rocq 9.2.0."
    }
  ],
  "affected": [
    {
      "source": "[email protected]",
      "affectedData": [
        {
          "vendor": "rocq-prover",
          "product": "rocq",
          "defaultStatus": "unaffected",
          "repo": "https://github.com/rocq-prover/rocq",
          "packageURL": "pkg:github/rocq-prover/rocq",
          "versions": [
            {
              "version": "0",
              "lessThan": "9.2.0",
              "versionType": "custom",
              "status": "affected"
            }
          ]
        }
      ]
    }
  ],
  "metrics": {
    "cvssMetricV40": [
      {
        "source": "[email protected]",
        "type": "Secondary",
        "cvssData": {
          "version": "4.0",
          "vectorString": "CVSS:4.0/AV:L/AC:L/AT:N/PR:N/UI:P/VC:N/VI:H/VA:N/SC:N/SI:N/SA:N/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X",
          "baseScore": 6.8,
          "baseSeverity": "MEDIUM",
          "attackVector": "LOCAL",
          "attackComplexity": "LOW",
          "attackRequirements": "NONE",
          "privilegesRequired": "NONE",
          "userInteraction": "PASSIVE",
          "vulnConfidentialityImpact": "NONE",
          "vulnIntegrityImpact": "HIGH",
          "vulnAvailabilityImpact": "NONE",
          "subConfidentialityImpact": "NONE",
          "subIntegrityImpact": "NONE",
          "subAvailabilityImpact": "NONE",
          "exploitMaturity": "NOT_DEFINED",
          "confidentialityRequirement": "NOT_DEFINED",
          "integrityRequirement": "NOT_DEFINED",
          "availabilityRequirement": "NOT_DEFINED",
          "modifiedAttackVector": "NOT_DEFINED",
          "modifiedAttackComplexity": "NOT_DEFINED",
          "modifiedAttackRequirements": "NOT_DEFINED",
          "modifiedPrivilegesRequired": "NOT_DEFINED",
          "modifiedUserInteraction": "NOT_DEFINED",
          "modifiedVulnConfidentialityImpact": "NOT_DEFINED",
          "modifiedVulnIntegrityImpact": "NOT_DEFINED",
          "modifiedVulnAvailabilityImpact": "NOT_DEFINED",
          "modifiedSubConfidentialityImpact": "NOT_DEFINED",
          "modifiedSubIntegrityImpact": "NOT_DEFINED",
          "modifiedSubAvailabilityImpact": "NOT_DEFINED",
          "Safety": "NOT_DEFINED",
          "Automatable": "NOT_DEFINED",
          "Recovery": "NOT_DEFINED",
          "valueDensity": "NOT_DEFINED",
          "vulnerabilityResponseEffort": "NOT_DEFINED",
          "providerUrgency": "NOT_DEFINED"
        }
      }
    ],
    "cvssMetricV31": [
      {
        "source": "[email protected]",
        "type": "Secondary",
        "cvssData": {
          "version": "3.1",
          "vectorString": "CVSS:3.1/AV:L/AC:L/PR:N/UI:R/S:C/C:N/I:H/A:N",
          "baseScore": 6.3,
          "baseSeverity": "MEDIUM",
          "attackVector": "LOCAL",
          "attackComplexity": "LOW",
          "privilegesRequired": "NONE",
          "userInteraction": "REQUIRED",
          "scope": "CHANGED",
          "confidentialityImpact": "NONE",
          "integrityImpact": "HIGH",
          "availabilityImpact": "NONE"
        },
        "exploitabilityScore": 1.8,
        "impactScore": 4.0
      }
    ],
    "ssvcV203": [
      {
        "source": "134c704f-9b21-4f2e-91b3-4a467353bcc0",
        "ssvcData": {
          "timestamp": "2026-08-26T15:46:51.503814Z",
          "id": "CVE-2026-72705",
          "options": [
            {
              "exploitation": "poc"
            },
            {
              "automatable": "no"
            },
            {
              "technicalImpact": "partial"
            }
          ],
          "role": "CISA Coordinator",
          "version": "2.0.3"
        }
      }
    ]
  },
  "weaknesses": [
    {
      "source": "[email protected]",
      "type": "Secondary",
      "description": [
        {
          "lang": "en",
          "value": "CWE-670"
        }
      ]
    }
  ],
  "references": [
    {
      "url": "https://github.com/endrazine/rocq-cve-poc-21683",
      "source": "[email protected]"
    },
    {
      "url": "https://github.com/rocq-prover/rocq",
      "source": "[email protected]"
    },
    {
      "url": "https://github.com/rocq-prover/rocq/issues/21683",
      "source": "[email protected]"
    },
    {
      "url": "https://github.com/rocq-prover/rocq/pull/21684",
      "source": "[email protected]"
    },
    {
      "url": "https://www.vulncheck.com/advisories/rocq-prover-before-guard-checker-accepts-fixpoint-passed-as-a-higher-order-argument",
      "source": "[email protected]"
    },
    {
      "url": "http://www.openwall.com/lists/oss-security/2026/10/26/6",
      "source": "af854a3a-2127-422b-91ae-364da2661108"
    }
  ]
}