CVE-2021-36647

4.7 MEDIUM
Published: January 17, 2023 Modified: November 03, 2025

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.

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CVSS v3.x Details

0.0 Low Medium High Critical 10.0
Vector String
CVSS:3.1/AV:L/AC:H/PR:L/UI:N/S:U/C:H/I:N/A:N

References to Advisories, Solutions, and Tools

Patch Vendor Advisory Exploit Third Party Advisory
https://github.com/ARMmbed/mbedtls/releases/
Source: cve@mitre.org
Third Party Advisory
https://kouzili.com/Load-Step.pdf
Source: cve@mitre.org
Third Party Advisory
https://github.com/ARMmbed/mbedtls/releases/
Source: af854a3a-2127-422b-91ae-364da2661108
Third Party Advisory
https://kouzili.com/Load-Step.pdf
Source: af854a3a-2127-422b-91ae-364da2661108
Third Party Advisory
https://tls.mbed.org/tech-updates/security-advisories/mbedtls-security-advisory-2021-07-1
Source: af854a3a-2127-422b-91ae-364da2661108
Vendor Advisory

7 reference(s) from NVD

Quick Stats

CVSS v3 Score
4.7 / 10.0
EPSS (Exploit Probability)
0.0%
10th percentile
Exploitation Status
Not in CISA KEV

Weaknesses (CWE)

Affected Vendors

arm