Instituto Nacional de ciberseguridad. Sección Incibe
Instituto Nacional de Ciberseguridad. Sección INCIBE-CERT

Go to Calendar     Go to Press Room     Go to Newsletters subscription

Search

CVE-2021-36647

Severity CVSS v4.0:
Pending analysis
Type:
CWE-327 Use of a Broken or Risky Cryptographic Algorithm
Publication date:
17/01/2023
Last modified:
03/11/2025

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.

Impact

Vector 3.x
CVSS:3.1/AV:L/AC:H/PR:L/UI:N/S:U/C:H/I:N/A:N CVSS v3.1 Severity and Metrics:

Base Score: 4.70 MEDIUM
Vector: CVSS:3.1/AV:L/AC:H/PR:L/UI:N/S:U/C:H/I:N/A:N

Attack Vector (AV): Local
Attack Complexity (AC): High
Privileges Required (PR): Low
User Interaction (UI): None
Scope (S): Unchanged
Confidentiality (C): High
Integrity (I): None
Availability (A): None

Base Score 3.x
4.70
Severity 3.x
MEDIUM

Vulnerable products and versions

CPE From Up to
cpe:2.3:a:arm:mbed_tls:*:*:*:*:*:*:*:* 2.16.11 (excluding)
cpe:2.3:a:arm:mbed_tls:*:*:*:*:*:*:*:* 2.17.0 (including) 2.27.0 (excluding)
cpe:2.3:a:arm:mbed_tls:*:*:*:*:*:*:*:* 2.28.0 (including) 3.0.0 (excluding)

To consult the complete list of CPE names with products and versions, see this page


References to Advisories, Solutions, and Tools