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4.7
MEDIUM CVSS 3.1
CVE-2021-36647
Mbed TLS Exposes RSA Private Keys in SGX Secure Enclave
Description

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.

INFO

Published Date :

Jan. 17, 2023, 9:15 p.m.

Last Modified :

April 8, 2025, 9:15 p.m.

Remotely Exploit :

No

Source :

[email protected]
Affected Products

The following products are affected by CVE-2021-36647 vulnerability. Even if cvefeed.io is aware of the exact versions of the products that are affected, the information is not represented in the table below.

ID Vendor Product Action
1 Arm mbed_tls
: Total Affected Vendor : 1 | Products : 1
CVSS Scores
The Common Vulnerability Scoring System is a standardized framework for assessing the severity of vulnerabilities in software and systems. We collect and displays CVSS scores from various sources for each CVE.
Score Version Severity Vector Exploitability Score Impact Score Source
CVSS 3.1 MEDIUM [email protected]
CVSS 3.1 MEDIUM 134c704f-9b21-4f2e-91b3-4a467353bcc0
Solution
This information is provided by the 3rd party feeds.
  • There is no known solution at this time.
Public PoC/Exploit Available at Github

CVE-2021-36647 has a 1 public PoC/Exploit available at Github. Go to the Public Exploits tab to see the list.

References to Advisories, Solutions, and Tools

Here, you will find a curated list of external links that provide in-depth information, practical solutions, and valuable tools related to CVE-2021-36647.

URL Resource
https://github.com/ARMmbed/mbedtls/releases/ Third Party Advisory
https://kouzili.com/Load-Step.pdf Third Party Advisory
https://tls.mbed.org/tech-updates/security-advisories/mbedtls-security-advisory-2021-07-1 Vendor Advisory
https://github.com/ARMmbed/mbedtls/releases/ Third Party Advisory
https://kouzili.com/Load-Step.pdf Third Party Advisory
https://tls.mbed.org/tech-updates/security-advisories/mbedtls-security-advisory-2021-07-1 Vendor Advisory
CWE - Common Weakness Enumeration

While CVE identifies specific instances of vulnerabilities, CWE categorizes the common flaws or weaknesses that can lead to vulnerabilities. CVE-2021-36647 is associated with the following CWEs:

Common Attack Pattern Enumeration and Classification (CAPEC)

Common Attack Pattern Enumeration and Classification (CAPEC) stores attack patterns, which are descriptions of the common attributes and approaches employed by adversaries to exploit the CVE-2021-36647 weaknesses.

We scan GitHub repositories to detect new proof-of-concept exploits. Following list is a collection of public exploits and proof-of-concepts, which have been published on GitHub (sorted by the most recently updated).

Profile Photo
kouzili/Load-Step

Prototype of the precise TrustZone execution control framework for exploring side-channel attacks.

Makefile Shell C Assembly Python

Updated: 1 year, 4 months ago
4 stars 0 fork 0 watcher
Born at : Jan. 26, 2022, 12:20 p.m. This repo has been linked 1 different CVEs too.

Results are limited to the first 15 repositories due to potential performance issues.

The following list is the news that have been mention CVE-2021-36647 vulnerability anywhere in the article.

Results are limited to the first 20 news articles due to potential performance issues.

The following table lists the changes that have been made to the CVE-2021-36647 vulnerability over time.

Vulnerability history details can be useful for understanding the evolution of a vulnerability, and for identifying the most recent changes that may impact the vulnerability's severity, exploitability, or other characteristics.

  • CVE Modified by 134c704f-9b21-4f2e-91b3-4a467353bcc0

    Apr. 08, 2025

    Action Type Old Value New Value
    Added CVSS V3.1 AV:L/AC:H/PR:L/UI:N/S:U/C:H/I:N/A:N
    Added CWE CWE-327
  • CVE Modified by af854a3a-2127-422b-91ae-364da2661108

    Nov. 21, 2024

    Action Type Old Value New Value
    Added Reference https://github.com/ARMmbed/mbedtls/releases/
    Added Reference https://kouzili.com/Load-Step.pdf
    Added Reference https://tls.mbed.org/tech-updates/security-advisories/mbedtls-security-advisory-2021-07-1
  • CVE Modified by [email protected]

    May. 14, 2024

    Action Type Old Value New Value
  • Initial Analysis by [email protected]

    Jan. 27, 2023

    Action Type Old Value New Value
    Added CVSS V3.1 NIST AV:L/AC:H/PR:L/UI:N/S:U/C:H/I:N/A:N
    Changed Reference Type https://github.com/ARMmbed/mbedtls/releases/ No Types Assigned https://github.com/ARMmbed/mbedtls/releases/ Third Party Advisory
    Changed Reference Type https://kouzili.com/Load-Step.pdf No Types Assigned https://kouzili.com/Load-Step.pdf Third Party Advisory
    Changed Reference Type https://tls.mbed.org/tech-updates/security-advisories/mbedtls-security-advisory-2021-07-1 No Types Assigned https://tls.mbed.org/tech-updates/security-advisories/mbedtls-security-advisory-2021-07-1 Vendor Advisory
    Added CWE NIST CWE-327
    Added CPE Configuration OR *cpe:2.3:a:arm:mbed_tls:*:*:*:*:*:*:*:* versions up to (excluding) 2.16.11 *cpe:2.3:a:arm:mbed_tls:*:*:*:*:*:*:*:* versions from (including) 2.17.0 up to (excluding) 2.27.0 *cpe:2.3:a:arm:mbed_tls:*:*:*:*:*:*:*:* versions from (including) 2.28.0 up to (excluding) 3.0.0
EPSS is a daily estimate of the probability of exploitation activity being observed over the next 30 days. Following chart shows the EPSS score history of the vulnerability.
Vulnerability Scoring Details
Base CVSS Score: 4.7
Attack Vector
Attack Complexity
Privileges Required
User Interaction
Scope
Confidentiality Impact
Integrity Impact
Availability Impact
Exploit Prediction

EPSS is a daily estimate of the probability of exploitation activity being observed over the next 30 days.

0.03 }} -0.01%

score

0.06639

percentile