← Back to CVE Explorer

CVE-2026-44362

Full vulnerability record from the local CVENow database.

Description

OP-TEE is a Trusted Execution Environment (TEE) designed as companion to a non-secure Linux kernel running on Arm; Cortex-A cores using the TrustZone technology. Starting in version 3.20.0 and prior to version 4.11.0, a vulnerability in OP-TEE’s subkey rollback protection allows the use of revoked or older subkey versions because the system fails to propagate versioning data during the Trusted Application (TA) loading process. In `core/crypto/signed_hdr.c`, the function `shdr_load_pub_key()` parses subkey headers but does not assign the `subkey_version` to the runtime `shdr_pub_key` structure. As a result, the `key->version` field remains at zero regardless of the version specified in the header. When `ree_fs_ta_open()` in `core/kernel/ree_fs_ta.c` calls `check_update_version()`, it passes this zeroed version to the rollback database. Because the database never receives a non-zero version to record, it never advances, effectively bypassing the rollback check and allowing TAs signed with downgraded subkey chains to load successfully. This impacts OP-TEE mainline configurations that utilize subkey-based signing chains for Trusted Application (TA) authentication. Version 4.11.0 contains a patch. No known workarounds are available.

Severity
MEDIUM
CVSS score
5.5 (v3.1)
Vulnerability status
Analyzed
Source identifier
Published
2026-07-06 20:16:33.950000
Last modified
2026-10-25 20:10:00.147000
View original CVE JSON
{
  "id": "CVE-2026-44362",
  "sourceIdentifier": "[email protected]",
  "published": "2026-07-06T20:16:33.950",
  "lastModified": "2026-10-25T20:10:00.147",
  "vulnStatus": "Analyzed",
  "cveTags": [],
  "descriptions": [
    {
      "lang": "en",
      "value": "OP-TEE is a Trusted Execution Environment (TEE) designed as companion to a non-secure Linux kernel running on Arm; Cortex-A cores using the TrustZone technology. Starting in version 3.20.0 and prior to version 4.11.0, a vulnerability in OP-TEE’s subkey rollback protection allows the use of revoked or older subkey versions because the system fails to propagate versioning data during the Trusted Application (TA) loading process. In `core/crypto/signed_hdr.c`, the function `shdr_load_pub_key()` parses subkey headers but does not assign the `subkey_version` to the runtime `shdr_pub_key` structure. As a result, the `key->version` field remains at zero regardless of the version specified in the header. When `ree_fs_ta_open()` in `core/kernel/ree_fs_ta.c` calls `check_update_version()`, it passes this zeroed version to the rollback database. Because the database never receives a non-zero version to record, it never advances, effectively bypassing the rollback check and allowing TAs signed with downgraded subkey chains to load successfully. This impacts OP-TEE mainline configurations that utilize subkey-based signing chains for Trusted Application (TA) authentication. Version 4.11.0 contains a patch. No known workarounds are available."
    },
    {
      "lang": "es",
      "value": "OP-TEE es un Entorno de Ejecución Confiable (TEE) diseñado como compañero de un kernel de Linux no seguro ejecutándose en núcleos Arm Cortex-A utilizando la tecnología TrustZone. A partir de la versión 3.20.0 y anterior a la versión 4.11.0, una vulnerabilidad en la protección de reversión de subclave de OP-TEE permite el uso de versiones de subclave revocadas o más antiguas porque el sistema no propaga los datos de versionado durante el proceso de carga de la Aplicación Confiable (TA). En ’core/crypto/signed_hdr.c’, la función ’shdr_load_pub_key()’ analiza los encabezados de subclave pero no asigna la ’subkey_version’ a la estructura ’shdr_pub_key’ en tiempo de ejecución. Como resultado, el campo ’key  ->  version’ permanece en cero independientemente de la versión especificada en el encabezado. Cuando ’ree_fs_ta_open()’ en ’core/kernel/ree_fs_ta.c’ llama a ’check_update_version()’, pasa esta versión puesta a cero a la base de datos de reversión. Debido a que la base de datos nunca recibe una versión no nula para registrar, nunca avanza, eludiendo efectivamente la verificación de reversión y permitiendo que las TA firmadas con cadenas de subclaves degradadas se carguen correctamente. Esto afecta a las configuraciones principales de OP-TEE que utilizan cadenas de firma basadas en subclaves para la autenticación de Aplicaciones Confiables (TA). La versión 4.11.0 contiene un parche. No se conocen soluciones alternativas disponibles."
    }
  ],
  "affected": [
    {
      "source": "[email protected]",
      "affectedData": [
        {
          "vendor": "OP-TEE",
          "product": "optee_os",
          "versions": [
            {
              "version": ">= 3.20.0, < 4.11.0",
              "status": "affected"
            }
          ]
        }
      ]
    }
  ],
  "metrics": {
    "cvssMetricV31": [
      {
        "source": "[email protected]",
        "type": "Secondary",
        "cvssData": {
          "version": "3.1",
          "vectorString": "CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:H/A:N",
          "baseScore": 5.5,
          "baseSeverity": "MEDIUM",
          "attackVector": "LOCAL",
          "attackComplexity": "LOW",
          "privilegesRequired": "LOW",
          "userInteraction": "NONE",
          "scope": "UNCHANGED",
          "confidentialityImpact": "NONE",
          "integrityImpact": "HIGH",
          "availabilityImpact": "NONE"
        },
        "exploitabilityScore": 1.8,
        "impactScore": 3.6
      }
    ],
    "ssvcV203": [
      {
        "source": "134c704f-9b21-4f2e-91b3-4a467353bcc0",
        "ssvcData": {
          "timestamp": "2026-07-06T20:51:43.694755Z",
          "id": "CVE-2026-44362",
          "options": [
            {
              "exploitation": "none"
            },
            {
              "automatable": "no"
            },
            {
              "technicalImpact": "partial"
            }
          ],
          "role": "CISA Coordinator",
          "version": "2.0.3"
        }
      }
    ]
  },
  "weaknesses": [
    {
      "source": "[email protected]",
      "type": "Secondary",
      "description": [
        {
          "lang": "en",
          "value": "CWE-285"
        }
      ]
    }
  ],
  "configurations": [
    {
      "nodes": [
        {
          "operator": "OR",
          "negate": false,
          "cpeMatch": [
            {
              "vulnerable": true,
              "criteria": "cpe:2.3:o:trustedfirmware:op-tee:*:*:*:*:*:*:*:*",
              "versionStartIncluding": "3.20.0",
              "versionEndIncluding": "4.10.0",
              "matchCriteriaId": "D8F56A2E-B76A-4B45-AF68-2036283D85D6"
            }
          ]
        }
      ]
    }
  ],
  "references": [
    {
      "url": "https://github.com/OP-TEE/optee_os/security/advisories/GHSA-fhcg-pp56-8v75",
      "source": "[email protected]",
      "tags": [
        "Vendor Advisory"
      ]
    }
  ]
}