CVE-2026-33662 (GCVE-0-2026-33662)

Vulnerability from cvelistv5 – Published: 2026-04-24 18:13 – Updated: 2026-04-24 19:00
VLAI
Title
OP-TEE: RSASSA EMSA- PKCS1-v1_5 underflow in emsa_pkcs1_v1_5_encode()
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. From 3.8.0 to 4.10, in the function emsa_pkcs1_v1_5_encode() in core/drivers/crypto/crypto_api/acipher/rsassa.c, the amount of padding needed, "PS size", is calculated by subtracting the size of the digest and other fields required for the EMA-PKCS1-v1_5 encoding from the size of the modulus of the key. By selecting a small enough modulus, this subtraction can overflow. The padding is added as a string of 0xFF bytes with a call to memset(), and an underflowed integer will cause the memset() call to overwrite until OP-TEE crashes. This only affects platforms registering RSA acceleration.
Severity
7.5 (High)
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
SSVC
Exploitation: none Automatable: yes Technical Impact: partial
CISA Coordinator · CISA-ADP (v2.0.3)
Decision recorded 2026-04-24 19:00 UTC
CWE
  • CWE-190 - Integer Overflow or Wraparound
Assigner
GitHub_M CNA under the mitre root
CNA scorecard C 72/100 over 7886 records in the last 180 days details
References
Impacted products
Vendor Product Version CPE status
OP-TEE optee_os Affected: >= 3.8.0, <= 4.10
guessed Create a notification for this product.
Show details on NVD website
To clipboard 

{
  "containers": {
    "adp": [
      {
        "metrics": [
          {
            "other": {
              "content": {
                "id": "CVE-2026-33662",
                "options": [
                  {
                    "Exploitation": "none"
                  },
                  {
                    "Automatable": "yes"
                  },
                  {
                    "Technical Impact": "partial"
                  }
                ],
                "role": "CISA Coordinator",
                "timestamp": "2026-04-24T19:00:09.301248Z",
                "version": "2.0.3"
              },
              "type": "ssvc"
            }
          }
        ],
        "providerMetadata": {
          "dateUpdated": "2026-04-24T19:00:51.713Z",
          "orgId": "134c704f-9b21-4f2e-91b3-4a467353bcc0",
          "shortName": "CISA-ADP"
        },
        "title": "CISA ADP Vulnrichment"
      }
    ],
    "cna": {
      "affected": [
        {
          "product": "optee_os",
          "vendor": "OP-TEE",
          "versions": [
            {
              "status": "affected",
              "version": "\u003e= 3.8.0, \u003c= 4.10"
            }
          ]
        }
      ],
      "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. From 3.8.0 to 4.10, in the function emsa_pkcs1_v1_5_encode() in core/drivers/crypto/crypto_api/acipher/rsassa.c, the amount of padding needed, \"PS size\", is calculated by subtracting the size of the digest and other fields required for the EMA-PKCS1-v1_5 encoding from the size of the modulus of the key. By selecting a small enough modulus, this subtraction can overflow. The padding is added as a string of 0xFF bytes with a call to memset(), and an underflowed integer will cause the memset() call to overwrite until OP-TEE crashes. This only affects platforms registering RSA acceleration."
        }
      ],
      "metrics": [
        {
          "cvssV3_1": {
            "attackComplexity": "LOW",
            "attackVector": "NETWORK",
            "availabilityImpact": "HIGH",
            "baseScore": 7.5,
            "baseSeverity": "HIGH",
            "confidentialityImpact": "NONE",
            "integrityImpact": "NONE",
            "privilegesRequired": "NONE",
            "scope": "UNCHANGED",
            "userInteraction": "NONE",
            "vectorString": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H",
            "version": "3.1"
          }
        }
      ],
      "problemTypes": [
        {
          "descriptions": [
            {
              "cweId": "CWE-190",
              "description": "CWE-190: Integer Overflow or Wraparound",
              "lang": "en",
              "type": "CWE"
            }
          ]
        }
      ],
      "providerMetadata": {
        "dateUpdated": "2026-04-24T18:13:28.529Z",
        "orgId": "a0819718-46f1-4df5-94e2-005712e83aaa",
        "shortName": "GitHub_M"
      },
      "references": [
        {
          "name": "https://github.com/OP-TEE/optee_os/security/advisories/GHSA-4cf8-v5g3-73gr",
          "tags": [
            "x_refsource_CONFIRM"
          ],
          "url": "https://github.com/OP-TEE/optee_os/security/advisories/GHSA-4cf8-v5g3-73gr"
        }
      ],
      "source": {
        "advisory": "GHSA-4cf8-v5g3-73gr",
        "discovery": "UNKNOWN"
      },
      "title": "OP-TEE: RSASSA EMSA- PKCS1-v1_5 underflow in emsa_pkcs1_v1_5_encode()"
    }
  },
  "cveMetadata": {
    "assignerOrgId": "a0819718-46f1-4df5-94e2-005712e83aaa",
    "assignerShortName": "GitHub_M",
    "cveId": "CVE-2026-33662",
    "datePublished": "2026-04-24T18:13:28.529Z",
    "dateReserved": "2026-03-23T15:23:42.219Z",
    "dateUpdated": "2026-04-24T19:00:51.713Z",
    "state": "PUBLISHED"
  },
  "dataType": "CVE_RECORD",
  "dataVersion": "5.2",
  "vulnerability-lookup:meta": {
    "epss": {
      "cve": "CVE-2026-33662",
      "date": "2026-11-04",
      "epss": "0.00403",
      "percentile": "0.3468"
    },
    "nvd": {
      "cve": {
        "affected": [
          {
            "affectedData": [
              {
                "product": "optee_os",
                "vendor": "OP-TEE",
                "versions": [
                  {
                    "status": "affected",
                    "version": "\u003e= 3.8.0, \u003c= 4.10"
                  }
                ]
              }
            ],
            "source": "security-advisories@github.com"
          }
        ],
        "configurations": [
          {
            "nodes": [
              {
                "cpeMatch": [
                  {
                    "criteria": "cpe:2.3:o:trustedfirmware:op-tee:*:*:*:*:*:*:*:*",
                    "matchCriteriaId": "BF89E0A3-1EAB-4954-8F4C-3AA14C015E5E",
                    "versionEndIncluding": "4.10.0",
                    "versionStartIncluding": "3.8.0",
                    "vulnerable": true
                  }
                ],
                "negate": false,
                "operator": "OR"
              }
            ]
          }
        ],
        "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. From 3.8.0 to 4.10, in the function emsa_pkcs1_v1_5_encode() in core/drivers/crypto/crypto_api/acipher/rsassa.c, the amount of padding needed, \"PS size\", is calculated by subtracting the size of the digest and other fields required for the EMA-PKCS1-v1_5 encoding from the size of the modulus of the key. By selecting a small enough modulus, this subtraction can overflow. The padding is added as a string of 0xFF bytes with a call to memset(), and an underflowed integer will cause the memset() call to overwrite until OP-TEE crashes. This only affects platforms registering RSA acceleration."
          },
          {
            "lang": "es",
            "value": "OP-TEE es un Entorno de Ejecuci\u00f3n Confiable (TEE) dise\u00f1ado como compa\u00f1ero de un kernel de Linux no seguro ejecut\u00e1ndose en n\u00facleos Arm Cortex-A que utilizan la tecnolog\u00eda TrustZone. Desde la versi\u00f3n 3.8.0 hasta la 4.10, en la funci\u00f3n emsa_pkcs1_v1_5_encode() en core/drivers/crypto/crypto_api/acipher/rsassa.c, la cantidad de relleno necesaria, \u2019tama\u00f1o PS\u2019, se calcula restando el tama\u00f1o del digest y otros campos requeridos para la codificaci\u00f3n EMA-PKCS1-v1_5 del tama\u00f1o del m\u00f3dulo de la clave. Al seleccionar un m\u00f3dulo lo suficientemente peque\u00f1o, esta resta puede desbordarse. El relleno se a\u00f1ade como una cadena de bytes 0xFF con una llamada a memset(), y un entero desbordado por debajo har\u00e1 que la llamada a memset() sobrescriba hasta que OP-TEE falle. Esto solo afecta a las plataformas que registran aceleraci\u00f3n RSA."
          }
        ],
        "id": "CVE-2026-33662",
        "lastModified": "2026-10-26T22:10:00.163",
        "metrics": {
          "cvssMetricV31": [
            {
              "cvssData": {
                "attackComplexity": "LOW",
                "attackVector": "NETWORK",
                "availabilityImpact": "HIGH",
                "baseScore": 7.5,
                "baseSeverity": "HIGH",
                "confidentialityImpact": "NONE",
                "integrityImpact": "NONE",
                "privilegesRequired": "NONE",
                "scope": "UNCHANGED",
                "userInteraction": "NONE",
                "vectorString": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H",
                "version": "3.1"
              },
              "exploitabilityScore": 3.9,
              "impactScore": 3.6,
              "source": "security-advisories@github.com",
              "type": "Secondary"
            }
          ],
          "ssvcV203": [
            {
              "source": "134c704f-9b21-4f2e-91b3-4a467353bcc0",
              "ssvcData": {
                "id": "CVE-2026-33662",
                "options": [
                  {
                    "exploitation": "none"
                  },
                  {
                    "automatable": "yes"
                  },
                  {
                    "technicalImpact": "partial"
                  }
                ],
                "role": "CISA Coordinator",
                "timestamp": "2026-04-24T19:00:09.301248Z",
                "version": "2.0.3"
              }
            }
          ]
        },
        "published": "2026-04-24T19:17:09.997",
        "references": [
          {
            "source": "security-advisories@github.com",
            "tags": [
              "Patch",
              "Vendor Advisory"
            ],
            "url": "https://github.com/OP-TEE/optee_os/security/advisories/GHSA-4cf8-v5g3-73gr"
          }
        ],
        "sourceIdentifier": "security-advisories@github.com",
        "vulnStatus": "Analyzed",
        "weaknesses": [
          {
            "description": [
              {
                "lang": "en",
                "value": "CWE-190"
              }
            ],
            "source": "security-advisories@github.com",
            "type": "Secondary"
          }
        ]
      }
    },
    "redhat_vex": {
      "current_release_date": "2026-06-05T19:17:09+00:00",
      "cve": "CVE-2026-33662",
      "id": "CVE-2026-33662",
      "initial_release_date": "2026-01-01T00:00:00+00:00",
      "product_status:known_not_affected": "1",
      "source": "Red Hat CSAF VEX",
      "status": "final",
      "title": "OP-TEE: RSASSA EMSA- PKCS1-v1_5 underflow in emsa_pkcs1_v1_5_encode()",
      "url": "https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-33662.json",
      "version": "3"
    },
    "vulnrichment": {
      "containers": {
        "adp": [
          {
            "metrics": [
              {
                "other": {
                  "content": {
                    "id": "CVE-2026-33662",
                    "options": [
                      {
                        "Exploitation": "none"
                      },
                      {
                        "Automatable": "yes"
                      },
                      {
                        "Technical Impact": "partial"
                      }
                    ],
                    "role": "CISA Coordinator",
                    "timestamp": "2026-04-24T19:00:09.301248Z",
                    "version": "2.0.3"
                  },
                  "type": "ssvc"
                }
              }
            ],
            "providerMetadata": {
              "dateUpdated": "2026-04-24T19:00:15.848Z",
              "orgId": "134c704f-9b21-4f2e-91b3-4a467353bcc0",
              "shortName": "CISA-ADP"
            },
            "title": "CISA ADP Vulnrichment"
          }
        ],
        "cna": {
          "affected": [
            {
              "product": "optee_os",
              "vendor": "OP-TEE",
              "versions": [
                {
                  "status": "affected",
                  "version": "\u003e= 3.8.0, \u003c= 4.10"
                }
              ]
            }
          ],
          "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. From 3.8.0 to 4.10, in the function emsa_pkcs1_v1_5_encode() in core/drivers/crypto/crypto_api/acipher/rsassa.c, the amount of padding needed, \"PS size\", is calculated by subtracting the size of the digest and other fields required for the EMA-PKCS1-v1_5 encoding from the size of the modulus of the key. By selecting a small enough modulus, this subtraction can overflow. The padding is added as a string of 0xFF bytes with a call to memset(), and an underflowed integer will cause the memset() call to overwrite until OP-TEE crashes. This only affects platforms registering RSA acceleration."
            }
          ],
          "metrics": [
            {
              "cvssV3_1": {
                "attackComplexity": "LOW",
                "attackVector": "NETWORK",
                "availabilityImpact": "HIGH",
                "baseScore": 7.5,
                "baseSeverity": "HIGH",
                "confidentialityImpact": "NONE",
                "integrityImpact": "NONE",
                "privilegesRequired": "NONE",
                "scope": "UNCHANGED",
                "userInteraction": "NONE",
                "vectorString": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H",
                "version": "3.1"
              }
            }
          ],
          "problemTypes": [
            {
              "descriptions": [
                {
                  "cweId": "CWE-190",
                  "description": "CWE-190: Integer Overflow or Wraparound",
                  "lang": "en",
                  "type": "CWE"
                }
              ]
            }
          ],
          "providerMetadata": {
            "dateUpdated": "2026-04-24T18:13:28.529Z",
            "orgId": "a0819718-46f1-4df5-94e2-005712e83aaa",
            "shortName": "GitHub_M"
          },
          "references": [
            {
              "name": "https://github.com/OP-TEE/optee_os/security/advisories/GHSA-4cf8-v5g3-73gr",
              "tags": [
                "x_refsource_CONFIRM"
              ],
              "url": "https://github.com/OP-TEE/optee_os/security/advisories/GHSA-4cf8-v5g3-73gr"
            }
          ],
          "source": {
            "advisory": "GHSA-4cf8-v5g3-73gr",
            "discovery": "UNKNOWN"
          },
          "title": "OP-TEE: RSASSA EMSA- PKCS1-v1_5 underflow in emsa_pkcs1_v1_5_encode()"
        }
      },
      "cveMetadata": {
        "assignerOrgId": "a0819718-46f1-4df5-94e2-005712e83aaa",
        "assignerShortName": "GitHub_M",
        "cveId": "CVE-2026-33662",
        "datePublished": "2026-04-24T18:13:28.529Z",
        "dateReserved": "2026-03-23T15:23:42.219Z",
        "dateUpdated": "2026-04-24T19:00:51.713Z",
        "state": "PUBLISHED"
      },
      "dataType": "CVE_RECORD",
      "dataVersion": "5.2"
    }
  }
}



Log in or create an account to share your comment.




Tags
Taxonomy of the tags.




Drag nodes to arrange them. Double-click a related vulnerability to open it, or a source to visit its link. The Physics button on the left tunes the layout and the simulation; the legend at the bottom left hides or shows nodes by kind and by sighting type.

Forecast uses a logistic model when the trend is rising, or an exponential decay model when the trend is falling. Fitted via linearized least squares.

Sightings

Author Source Type Date Other

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.
Vulnerability timeline

Sightings and recorded dates, grouped by day · UTC

JSON

Loading timeline…




    Related by attack behaviour

    Vulnerabilities whose description is nearest to this one in the vector space of the CIRCL/vulnerability-attack-technique-biencoder model. This is a similarity search over the bi-encoder space (plain cosine), not a classification, and it has no measured accuracy.