MSRC_CVE-2021-36647
Vulnerability from csaf_microsoft - Published: 2023-01-04 00:00 - Updated: 2026-02-19 01:23Summary
Use of a Broken or Risky Cryptographic Algorithm in the function mbedtls_mpi_exp_mod() in lignum.c in Mbed TLS Mbed TLS all versions before 3.0.0 2.27.0 or 2.16.11 allows attackers with access to precise enough timing and memory access information (typically an untrusted operating system attacking a secure enclave such as SGX or the TrustZone secure world) to recover the private keys used in RSA.
Notes
Additional Resources: To determine the support lifecycle for your software, see the Microsoft Support Lifecycle: https://support.microsoft.com/lifecycle
Disclaimer: The information provided in the Microsoft Knowledge Base is provided \"as is\" without warranty of any kind. Microsoft disclaims all warranties, either express or implied, including the warranties of merchantability and fitness for a particular purpose. In no event shall Microsoft Corporation or its suppliers be liable for any damages whatsoever including direct, indirect, incidental, consequential, loss of business profits or special damages, even if Microsoft Corporation or its suppliers have been advised of the possibility of such damages. Some states do not allow the exclusion or limitation of liability for consequential or incidental damages so the foregoing limitation may not apply.
4.7 (Medium)
Vendor Fix
2.0.9-1:Security Update:https://learn.microsoft.com/en-us/azure/azure-linux/tutorial-azure-linux-upgrade
https://learn.microsoft.com/en-us/azure/azure-lin…
Vendor Fix
1.0.1-6:Security Update:https://learn.microsoft.com/en-us/azure/azure-linux/tutorial-azure-linux-upgrade
https://learn.microsoft.com/en-us/azure/azure-lin…
References
| URL | Category | |
|---|---|---|
{
"document": {
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"title": "Additional Resources"
},
{
"category": "legal_disclaimer",
"text": "The information provided in the Microsoft Knowledge Base is provided \\\"as is\\\" without warranty of any kind. Microsoft disclaims all warranties, either express or implied, including the warranties of merchantability and fitness for a particular purpose. In no event shall Microsoft Corporation or its suppliers be liable for any damages whatsoever including direct, indirect, incidental, consequential, loss of business profits or special damages, even if Microsoft Corporation or its suppliers have been advised of the possibility of such damages. Some states do not allow the exclusion or limitation of liability for consequential or incidental damages so the foregoing limitation may not apply.",
"title": "Disclaimer"
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{
"category": "self",
"summary": "CVE-2021-36647 Use of a Broken or Risky Cryptographic Algorithm in the function mbedtls_mpi_exp_mod() in lignum.c in Mbed TLS Mbed TLS all versions before 3.0.0 2.27.0 or 2.16.11 allows attackers with access to precise enough timing and memory access information (typically an untrusted operating system attacking a secure enclave such as SGX or the TrustZone secure world) to recover the private keys used in RSA. - VEX",
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},
{
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{
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"url": "https://www.first.org/cvss"
}
],
"title": "Use of a Broken or Risky Cryptographic Algorithm in the function mbedtls_mpi_exp_mod() in lignum.c in Mbed TLS Mbed TLS all versions before 3.0.0 2.27.0 or 2.16.11 allows attackers with access to precise enough timing and memory access information (typically an untrusted operating system attacking a secure enclave such as SGX or the TrustZone secure world) to recover the private keys used in RSA.",
"tracking": {
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},
"vulnerabilities": [
{
"cve": "CVE-2021-36647",
"cwe": {
"id": "CWE-327",
"name": "Use of a Broken or Risky Cryptographic Algorithm"
},
"flags": [
{
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"17084-3"
]
},
{
"label": "vulnerable_code_not_present",
"product_ids": [
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"17086-5"
]
}
],
"notes": [
{
"category": "general",
"text": "mitre",
"title": "Assigning CNA"
}
],
"product_status": {
"fixed": [
"12667-12139",
"12668-12139",
"12669-12139",
"12673-12139",
"12670-12140",
"12671-12140",
"12672-12140",
"19809-17086",
"17238-17086"
],
"known_affected": [
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"12139-11",
"12139-10",
"12139-6",
"12140-9",
"12140-8",
"12140-7",
"17086-1",
"17086-4"
],
"known_not_affected": [
"17086-2",
"17084-3",
"17086-5"
]
},
"references": [
{
"category": "self",
"summary": "CVE-2021-36647 Use of a Broken or Risky Cryptographic Algorithm in the function mbedtls_mpi_exp_mod() in lignum.c in Mbed TLS Mbed TLS all versions before 3.0.0 2.27.0 or 2.16.11 allows attackers with access to precise enough timing and memory access information (typically an untrusted operating system attacking a secure enclave such as SGX or the TrustZone secure world) to recover the private keys used in RSA. - VEX",
"url": "https://msrc.microsoft.com/csaf/vex/2023/msrc_cve-2021-36647.json"
}
],
"remediations": [
{
"category": "vendor_fix",
"date": "2023-01-23T00:00:00.000Z",
"details": "2.0.9-1:Security Update:https://learn.microsoft.com/en-us/azure/azure-linux/tutorial-azure-linux-upgrade",
"product_ids": [
"12139-12",
"12139-11",
"12139-10",
"12140-9",
"12140-8",
"12140-7"
],
"url": "https://learn.microsoft.com/en-us/azure/azure-linux/tutorial-azure-linux-upgrade"
},
{
"category": "vendor_fix",
"date": "2023-01-23T00:00:00.000Z",
"details": "1.0.1-6:Security Update:https://learn.microsoft.com/en-us/azure/azure-linux/tutorial-azure-linux-upgrade",
"product_ids": [
"12139-6",
"17086-1",
"17086-4"
],
"url": "https://learn.microsoft.com/en-us/azure/azure-linux/tutorial-azure-linux-upgrade"
}
],
"scores": [
{
"cvss_v3": {
"attackComplexity": "HIGH",
"attackVector": "LOCAL",
"availabilityImpact": "NONE",
"baseScore": 4.7,
"baseSeverity": "MEDIUM",
"confidentialityImpact": "HIGH",
"environmentalsScore": 0.0,
"integrityImpact": "NONE",
"privilegesRequired": "LOW",
"scope": "UNCHANGED",
"temporalScore": 4.7,
"userInteraction": "NONE",
"vectorString": "CVSS:3.1/AV:L/AC:H/PR:L/UI:N/S:U/C:H/I:N/A:N",
"version": "3.1"
},
"products": [
"12139-12",
"12139-11",
"12139-10",
"12139-6",
"12140-9",
"12140-8",
"12140-7",
"17086-1",
"17086-4"
]
}
],
"title": "Use of a Broken or Risky Cryptographic Algorithm in the function mbedtls_mpi_exp_mod() in lignum.c in Mbed TLS Mbed TLS all versions before 3.0.0 2.27.0 or 2.16.11 allows attackers with access to precise enough timing and memory access information (typically an untrusted operating system attacking a secure enclave such as SGX or the TrustZone secure world) to recover the private keys used in RSA."
}
]
}
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Experimental. This forecast is provided for visualization only and may change without notice. Do not use it for operational decisions.
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.
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