Security restrictions bypass in ARM mbed TLS

Published: 2018-08-28 | Updated: 2020-12-14
Risk Low
Patch available YES
Number of vulnerabilities 1
CVE-ID CVE-2018-1000520
Exploitation vector Network
Public exploit N/A
Vulnerable software
mbed TLS
Universal components / Libraries / Libraries used by multiple products

Vendor ARM

Security Bulletin

This security bulletin contains one low risk vulnerability.

1) Improper certificate validation

EUVDB-ID: #VU14538

Risk: Low

CVSSv3.1: 6.4 [CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:L/A:L/E:U/RL:O/RC:C]

CVE-ID: CVE-2018-1000520

CWE-ID: CWE-295 - Improper Certificate Validation

Exploit availability: No


The vulnerability allows a remote attacker to bypass security restrictions on the target system.

The vulnerability exists in the mbedtls_ssl_get_verify_result() function of ARM mbed Transport Layer Security (TLS) due to improper validation of signed certificates. A remote attacker on a peer system can use a negotiated cipher suite of an Elliptic Curve Diffie-Hellman (ECDH) key exchange and Rivest-Shamir-Adleman (RSA) signed certificate (TLS-ECDH-RSA-*) to cause the targeted system to accept an arbitrary ECDSA signed certificate.


Install update from vendor's website.

Vulnerable software versions

mbed TLS: 1.3.0 - 2.7.0

External links

Q & A

Can this vulnerability be exploited remotely?

Yes. This vulnerability can be exploited by a remote non-authenticated attacker via the Internet.

Is there known malware, which exploits this vulnerability?

No. We are not aware of malware exploiting this vulnerability.