Vulnerability Monitor

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CVE-2020-36478

An issue was discovered in Mbed TLS before 2.25.0 (and before 2.16.9 LTS and before 2.7.18 LTS). A NULL algorithm parameters entry looks identical to an array of REAL (size zero) and thus the certificate is considered valid. However, if the parameters do not match in any way, then the certificate should be considered invalid.

Security Impact Summary

This vulnerability carries a HIGH severity rating with a CVSS v3.1 score of 7.5, indicating it can be exploited remotely over the network with relatively low complexity without requiring user interaction and does not require pre-existing privileges . The vulnerability impacts integrity (unauthorized modifications), for affected systems. Impacting 14 products from arm, from siemens, from siemens and 11 others, organizations running these solutions should prioritize assessment and patching.

Historical Context

Reported in 2021, this vulnerability emerged during an era marked by increased sophistication in supply chain attacks, cloud infrastructure vulnerabilities, and software-as-a-service (SaaS) security challenges. Security practices during this period emphasized zero-trust architectures, container security, and API protection.

Published

2021-08-23T02:15:07.097

Last Modified

2024-11-21T05:29:38.247

Status

Modified

Source

[email protected]

Severity

CVSSv3.1: 7.5 (HIGH)

CVSSv2 Vector

AV:N/AC:L/Au:N/C:N/I:P/A:N

Access Vector: NETWORK
Access Complexity: LOW
Authentication: NONE
Confidentiality Impact: NONE
Integrity Impact: PARTIAL
Availability Impact: NONE

Exploitability Score

10.0

Impact Score

2.9

Weaknesses

Type: Primary
CWE-295

Affected Vendors & Products

Type	Vendor	Product	Version/Range	Vulnerable?
Application	arm	mbed_tls	< 2.7.18	Yes
Application	arm	mbed_tls	< 2.16.9	Yes
Application	arm	mbed_tls	< 2.25.0	Yes
Operating System	siemens	logo\!_cmr2020_firmware	< 2.2	Yes
Hardware	siemens	logo\!_cmr2020	-	No
Operating System	siemens	logo\!_cmr2040_firmware	< 2.2	Yes
Hardware	siemens	logo\!_cmr2040	-	No
Operating System	siemens	simatic_rtu3031c_firmware	*	Yes
Hardware	siemens	simatic_rtu3031c	-	No
Operating System	siemens	simatic_rtu3041c_firmware	*	Yes
Hardware	siemens	simatic_rtu3041c	-	No
Operating System	siemens	simatic_rtu3030c_firmware	*	Yes
Hardware	siemens	simatic_rtu3030c	-	No
Operating System	siemens	simatic_rtu3000c_firmware	*	Yes
Hardware	siemens	simatic_rtu3000c	-	No
Operating System	debian	debian_linux	9.0	Yes
Operating System	debian	debian_linux	10.0	Yes

References

https://cert-portal.siemens.com/productcert/pdf/ssa-756638.pdf Patch, Third Party Advisory ([email protected])
https://github.com/ARMmbed/mbedtls/issues/3629 Exploit, Third Party Advisory ([email protected])
https://github.com/ARMmbed/mbedtls/releases/tag/v2.16.9 Release Notes, Third Party Advisory ([email protected])
https://github.com/ARMmbed/mbedtls/releases/tag/v2.25.0 Release Notes, Third Party Advisory ([email protected])
https://github.com/ARMmbed/mbedtls/releases/tag/v2.7.18 Release Notes, Third Party Advisory ([email protected])
https://lists.debian.org/debian-lts-announce/2021/11/msg00021.html Mailing List, Third Party Advisory ([email protected])
https://lists.debian.org/debian-lts-announce/2022/12/msg00036.html Mailing List, Third Party Advisory ([email protected])
https://cert-portal.siemens.com/productcert/pdf/ssa-756638.pdf Patch, Third Party Advisory (af854a3a-2127-422b-91ae-364da2661108)
https://github.com/ARMmbed/mbedtls/issues/3629 Exploit, Third Party Advisory (af854a3a-2127-422b-91ae-364da2661108)
https://github.com/ARMmbed/mbedtls/releases/tag/v2.16.9 Release Notes, Third Party Advisory (af854a3a-2127-422b-91ae-364da2661108)
https://github.com/ARMmbed/mbedtls/releases/tag/v2.25.0 Release Notes, Third Party Advisory (af854a3a-2127-422b-91ae-364da2661108)
https://github.com/ARMmbed/mbedtls/releases/tag/v2.7.18 Release Notes, Third Party Advisory (af854a3a-2127-422b-91ae-364da2661108)
https://lists.debian.org/debian-lts-announce/2021/11/msg00021.html Mailing List, Third Party Advisory (af854a3a-2127-422b-91ae-364da2661108)
https://lists.debian.org/debian-lts-announce/2022/12/msg00036.html Mailing List, Third Party Advisory (af854a3a-2127-422b-91ae-364da2661108)

How SecUtils Interprets This CVE

SecUtils normalizes and enriches National Vulnerability Database (NVD) records by standardizing vendor and product identifiers, aggregating vulnerability metadata from both NVD and MITRE sources, and providing structured context for security teams. For arm's affected products, we extract Common Platform Enumeration (CPE) data, Common Weakness Enumeration (CWE) classifications, CVSS severity metrics, and reference data to enable rapid vulnerability prioritization and asset correlation. This record contains no exploit code, proof-of-concept instructions, or attack methodologies—only defensive intelligence necessary for patch management, risk assessment, and security operations.