CVE-2020-36478: High severity mbed tls vulnerability

Published Aug 23, 2021
·
Updated

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.

Affected Software

17 affected components
Arm mbed TLS<2.7.18
Arm mbed TLS>=2.8.0<2.16.9
Arm mbed TLS>=2.17.0<2.25.0
Siemens Logo\! Cmr2020 Firmware<2.2
Siemens Logo\! Cmr2020
Siemens Logo\! Cmr2040 Firmware<2.2
Siemens Logo\! Cmr2040
Siemens Simatic Rtu3031c Firmware
Siemens Simatic Rtu3031c
Siemens Simatic Rtu3041c Firmware
Siemens Simatic Rtu3041c
Siemens Simatic Rtu3030c Firmware
Siemens Simatic Rtu3030c
Siemens Simatic Rtu3000c Firmware
Siemens Simatic Rtu3000c
Debian Debian Linux=9.0
Debian Debian Linux=10.0

Event History

Aug 23, 2021
CVE Published
via MITRE·12:00 AM
Data Sourced
via MITRE·12:00 AM
Description
Sep 4, 2025
Data Sourced
via Microsoft·05:05 AM
DescriptionSeverityWeakness
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Frequently Asked Questions

1

What is CVE-2020-36478?

CVE-2020-36478 is a vulnerability in Mbed TLS before 2.25.0 (and before 2.16.9 LTS and before 2.7.18 LTS) that allows a NULL algorithm parameters entry to be considered valid.

2

How does CVE-2020-36478 affect ARM mbed TLS?

CVE-2020-36478 affects ARM mbed TLS versions before 2.25.0 (and before 2.16.9 LTS and before 2.7.18 LTS) by allowing a NULL algorithm parameters entry to be considered valid.

3

Is Siemens Logo! CMR2020 Firmware affected by CVE-2020-36478?

Siemens Logo! CMR2020 Firmware versions up to 2.2 are affected by CVE-2020-36478.

4

How can I fix CVE-2020-36478?

To fix CVE-2020-36478, update to Mbed TLS version 2.25.0 or later (or versions 2.16.9 LTS and 2.7.18 LTS if available).

5

What is the severity of CVE-2020-36478?

CVE-2020-36478 has a severity rating of 7.5 (high).

Contact

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