fkie_cve-2025-49600
Vulnerability from fkie_nvd
Published
2025-07-04 15:15
Modified
2025-07-17 15:59
Severity ?
Summary
In MbedTLS 3.3.0 before 3.6.4, mbedtls_lms_verify may accept invalid signatures if hash computation fails and internal errors go unchecked, enabling LMS (Leighton-Micali Signature) forgery in a fault scenario. Specifically, unchecked return values in mbedtls_lms_verify allow an attacker (who can induce a hardware hash accelerator fault) to bypass LMS signature verification by reusing stale stack data, resulting in acceptance of an invalid signature. In mbedtls_lms_verify, the return values of the internal Merkle tree functions create_merkle_leaf_value and create_merkle_internal_value are not checked. These functions return an integer that indicates whether the call succeeded or not. If a failure occurs, the output buffer (Tc_candidate_root_node) may remain uninitialized, and the result of the signature verification is unpredictable. When the software implementation of SHA-256 is used, these functions will not fail. However, with hardware-accelerated hashing, an attacker could use fault injection against the accelerator to bypass verification.
References
{
"configurations": [
{
"nodes": [
{
"cpeMatch": [
{
"criteria": "cpe:2.3:a:arm:mbed_tls:*:*:*:*:*:*:*:*",
"matchCriteriaId": "670EA016-8FA4-4F42-A180-11243DCCD155",
"versionEndExcluding": "3.6.4",
"versionStartIncluding": "3.3.0",
"vulnerable": true
}
],
"negate": false,
"operator": "OR"
}
]
}
],
"cveTags": [],
"descriptions": [
{
"lang": "en",
"value": "In MbedTLS 3.3.0 before 3.6.4, mbedtls_lms_verify may accept invalid signatures if hash computation fails and internal errors go unchecked, enabling LMS (Leighton-Micali Signature) forgery in a fault scenario. Specifically, unchecked return values in mbedtls_lms_verify allow an attacker (who can induce a hardware hash accelerator fault) to bypass LMS signature verification by reusing stale stack data, resulting in acceptance of an invalid signature. In mbedtls_lms_verify, the return values of the internal Merkle tree functions create_merkle_leaf_value and create_merkle_internal_value are not checked. These functions return an integer that indicates whether the call succeeded or not. If a failure occurs, the output buffer (Tc_candidate_root_node) may remain uninitialized, and the result of the signature verification is unpredictable. When the software implementation of SHA-256 is used, these functions will not fail. However, with hardware-accelerated hashing, an attacker could use fault injection against the accelerator to bypass verification."
},
{
"lang": "es",
"value": "En MbedTLS 3.3.0 anterior a 3.6.4, mbedtls_lms_verify pod\u00eda aceptar firmas no v\u00e1lidas si el c\u00e1lculo del hash fallaba y los errores internos no se verificaban, lo que permit\u00eda la falsificaci\u00f3n de la firma LMS (Leighton-Micali Signature) en un escenario de fallo. Espec\u00edficamente, los valores de retorno no verificados en mbedtls_lms_verify permiten a un atacante (que puede inducir un fallo en el acelerador de hash de hardware) omitir la verificaci\u00f3n de la firma LMS reutilizando datos obsoletos de la pila, lo que resulta en la aceptaci\u00f3n de una firma no v\u00e1lida. En mbedtls_lms_verify, los valores de retorno de las funciones internas del \u00e1rbol de Merkle create_merkle_leaf_value y create_merkle_internal_value no se verifican. Estas funciones devuelven un entero que indica si la llamada se realiz\u00f3 correctamente. Si se produce un fallo, el b\u00fafer de salida (Tc_candidate_root_node) puede permanecer sin inicializar, y el resultado de la verificaci\u00f3n de la firma es impredecible. Al implementar SHA-256 en software, estas funciones no fallan. Sin embargo, con el hashing acelerado por hardware, un atacante podr\u00eda usar la inyecci\u00f3n de fallos contra el acelerador para eludir la verificaci\u00f3n."
}
],
"id": "CVE-2025-49600",
"lastModified": "2025-07-17T15:59:03.633",
"metrics": {
"cvssMetricV31": [
{
"cvssData": {
"attackComplexity": "HIGH",
"attackVector": "PHYSICAL",
"availabilityImpact": "NONE",
"baseScore": 4.9,
"baseSeverity": "MEDIUM",
"confidentialityImpact": "NONE",
"integrityImpact": "HIGH",
"privilegesRequired": "NONE",
"scope": "CHANGED",
"userInteraction": "NONE",
"vectorString": "CVSS:3.1/AV:P/AC:H/PR:N/UI:N/S:C/C:N/I:H/A:N",
"version": "3.1"
},
"exploitabilityScore": 0.5,
"impactScore": 4.0,
"source": "cve@mitre.org",
"type": "Secondary"
}
]
},
"published": "2025-07-04T15:15:22.277",
"references": [
{
"source": "cve@mitre.org",
"tags": [
"Third Party Advisory"
],
"url": "https://github.com/Mbed-TLS/mbedtls-docs/blob/main/security-advisories/mbedtls-security-advisory-2025-06-3.md"
}
],
"sourceIdentifier": "cve@mitre.org",
"vulnStatus": "Analyzed",
"weaknesses": [
{
"description": [
{
"lang": "en",
"value": "CWE-325"
}
],
"source": "cve@mitre.org",
"type": "Primary"
}
]
}
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Sightings
| Author | Source | Type | Date |
|---|
Nomenclature
- Seen: The vulnerability was mentioned, discussed, or seen somewhere by the user.
- Confirmed: The vulnerability is confirmed from an analyst perspective.
- Exploited: This vulnerability was exploited and seen by the user reporting the sighting.
- Patched: This vulnerability was successfully patched by the user reporting the sighting.
- Not exploited: This vulnerability was not exploited or seen by the user reporting the sighting.
- Not confirmed: The user expresses doubt about the veracity of the vulnerability.
- Not patched: This vulnerability was not successfully patched by the user reporting the sighting.
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