OP-TEE's subkey rollback protection can be bypassed with older subkey versions

{
  "id": "eb102515ecb1a4847cbc40d314eedb687d8b397005117ee4d1f4d18bcd9c3a19",
  "url": "https://osv.dev/vulnerability/CVE-2026-44362",
  "method": "structured",
  "payload": {
    "kind": "advisory",
    "title": "OP-TEE's subkey rollback protection can be bypassed with older subkey versions",
    "summary": "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.",
    "evidence": "osv:CVE-2026-44362",
    "products": [],
    "severity": "medium",
    "structured": {
      "id": "CVE-2026-44362",
      "aliases": [
        "CVE-2026-44362",
        "GHSA-fhcg-pp56-8v75"
      ],
      "metrics": [
        {
          "type": "CVSS_V3",
          "score": "CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:H/A:N"
        }
      ],
      "affected": [
        {
          "ranges": [
            {
              "repo": "https://github.com/op-tee/optee_os",
              "type": "GIT",
              "events": [
                {
                  "introduced": "8e74d47616a20eaa23ca692f4bbbf917a236ed94"
                },
                {
                  "fixed": "f54190f22611dd5ad5d22546fd4209aa100f56bd"
                }
              ],
              "database_specific": {
                "extracted_events": [
                  {
                    "range": [
                      {
                        "introduced": "3.20.0"
                      },
                      {
                        "fixed": "4.11.0"
                      }
                    ],
                    "source": "AFFECTED_FIELD",
                    "strategy": "StringRangeExpression"
                  }
                ]
              }
            }
          ],
          "versions": [
            "4.11.0-rc1",
            "4.10.0",
            "4.10.0-rc1",
            "4.9.0",
            "4.9.0-rc1",
            "4.8.0",
            "4.8.0-rc1",
            "4.7.0",
            "4.7.0-rc1",
            "4.6.0",
            "4.6.0-rc1",
            "4.5.0",
            "4.5.0-rc1",
            "4.4.0",
            "4.4.0-rc1",
            "4.3.0",
            "4.3.0-rc1",
            "4.2.0",
            "4.2.0-rc1",
            "4.1.0",
            "4.1.0-rc1",
            "4.0.0",
            "4.0.0-rc1",
            "3.22.0",
            "3.22.0-rc1",
            "3.21.0",
            "3.21.0-rc1",
            "3.20.0"
          ],
          "database_specific": {
            "source": "https://storage.googleapis.com/cve-osv-conversion/osv-output/CVE-2026-44362.json"
          }
        }
      ],
      "modified": "2026-10-28T02:30:35.346464015Z",
      "provider": "osv",
      "references": [
        "https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/44xxx/CVE-2026-44362.json",
        "https://github.com/OP-TEE/optee_os/security/advisories/GHSA-fhcg-pp56-8v75",
        "https://nvd.nist.gov/vuln/detail/CVE-2026-44362"
      ],
      "provider_metadata": {
        "cwe_ids": [
          "CWE-285"
        ],
        "cna_assigner": "GitHub_M",
        "osv_generated_from": "https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/44xxx/CVE-2026-44362.json"
      }
    },
    "related_cves": [
      {
        "value": "CVE-2026-44362",
        "evidence": "/id"
      }
    ],
    "security_relevant": true,
    "severity_evidence": "/severity/0/score"
  },
  "source_id": "core-osv",
  "document_id": 502931,
  "published_at": "2026-07-06T19:33:48.666+00:00"
}