CVE-2020-36478
mediumpriority · track · 30EPSS 0.011 · 66 %ileDEEURUUSEPSS · scored 2026-10-27
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.
remediations
Vendor fix, mitigation, or workaround guidance, as published by each source.
A vendor fix is available.
- FixedLOGO! CMR2020siemens_psirt
Update to V2.2 or later version
https://support.industry.siemens.com/cs/ww/en/view/109800267/ - FixedLOGO! CMR2040siemens_psirt
Update to V2.2 or later version
https://support.industry.siemens.com/cs/ww/en/view/109800267/ - FixedSIMATIC RTU3010Csiemens_psirt
Update to V5.0.14 or later version
https://support.industry.siemens.com/cs/ww/en/view/109810215/ - FixedSIMATIC RTU3030Csiemens_psirt
Update to V5.0.14 or later version
https://support.industry.siemens.com/cs/ww/en/view/109810215/ - FixedSIMATIC RTU3031Csiemens_psirt
Update to V5.0.14 or later version
https://support.industry.siemens.com/cs/ww/en/view/109810215/ - FixedSIMATIC RTU3041Csiemens_psirt
Update to V5.0.14 or later version
https://support.industry.siemens.com/cs/ww/en/view/109810215/ - FixedLOGO! CMR2020cisa_csaf_ot
For the SIMATIC RTU 3000 family, Siemens recommends affected users use the certificate projection feature to pin the valid certificates of external servers providing services to the RTU/CMR devices. Refer to the product manual for further information.
- FixedLOGO! CMR2040cisa_csaf_ot
For the SIMATIC RTU 3000 family, Siemens recommends affected users use the certificate projection feature to pin the valid certificates of external servers providing services to the RTU/CMR devices. Refer to the product manual for further information.
- FixedSIMATIC RTU 3000 familycisa_csaf_ot
For the SIMATIC RTU 3000 family, Siemens recommends affected users use the certificate projection feature to pin the valid certificates of external servers providing services to the RTU/CMR devices. Refer to the product manual for further information.
- MitigationLOGO! CMR2020siemens_psirt
For CVE-2020-36478: Use the certificate projection feature to pin the valid certificates of external servers providing services to the RTU/CMR devices. See the manual for further information
- MitigationLOGO! CMR2040siemens_psirt
For CVE-2020-36478: Use the certificate projection feature to pin the valid certificates of external servers providing services to the RTU/CMR devices. See the manual for further information
- MitigationSIMATIC RTU3010Csiemens_psirt
For CVE-2020-36478: Use the certificate projection feature to pin the valid certificates of external servers providing services to the RTU/CMR devices. See the manual for further information
- MitigationSIMATIC RTU3030Csiemens_psirt
For CVE-2020-36478: Use the certificate projection feature to pin the valid certificates of external servers providing services to the RTU/CMR devices. See the manual for further information
- MitigationSIMATIC RTU3031Csiemens_psirt
For CVE-2020-36478: Use the certificate projection feature to pin the valid certificates of external servers providing services to the RTU/CMR devices. See the manual for further information
- MitigationSIMATIC RTU3041Csiemens_psirt
For CVE-2020-36478: Use the certificate projection feature to pin the valid certificates of external servers providing services to the RTU/CMR devices. See the manual for further information
cvss
Technical severity, 0–10. One row per scoring source.
base score 0–10 · higher = more severe · hover a vector to decode⚠ sources disagree · medium–high · 5–7.5
weaknesses
The CWE weakness classes this flaw belongs to.
affected products (31)
Products and version ranges known to be affected.
advisories (2)
Vendor and ecosystem advisories describing this.
- SSA-756638SSA-756638: Vulnerabilities in Third-Party Component Mbed TLS of LOGO! CMR Family and SIMATIC RTU 3000 Family2021-09-14csaf · siemens_psirtDE
Devices of the LOGO! CMR family and the SIMATIC RTU 3000 family are affected by several vulnerabilities in the third party component Mbed TLS. They could allow an attacker with access to any of the interfaces of an affected device to impact the availability or to communicate with invalid certificates. Siemens has released updates for the affected products and recommends to update to the latest versions.
- ICSA-21-257-20Siemens LOGO! CMR and SIMATIC RTU 30002021-09-14icsa · cisa_csaf_otUS
Successful exploitation of these vulnerabilities could allow an attacker with access to any of the interfaces of an affected device to impact the availability or to communicate with invalid certificates.
also known as (4)
Other names and identifiers for this entity.
sources
Which sources assert this record, and when.
references (26)
External citations — patches, advisories, analysis.
- https://cert-portal.siemens.com/productcert/pdf/ssa-756638.pdfcnnvd
- https://github.com/ARMmbed/mbedtls/issues/3629cnnvd
- https://github.com/ARMmbed/mbedtls/releases/tag/v2.16.9cnnvd
- https://github.com/ARMmbed/mbedtls/releases/tag/v2.25.0cnnvd
- https://github.com/ARMmbed/mbedtls/releases/tag/v2.7.18cnnvd
- https://lists.debian.org/debian-lts-announce/2021/11/msg00021.htmlcnnvd
- https://lists.debian.org/debian-lts-announce/2022/12/msg00036.htmlcnnvd
- https://packetstormsecurity.com/files/170461/Gentoo-Linux-Security-Advisory-202301-08.htmlcnnvd
Attackers weaponise vulnerabilities like this against internet-exposed services. See what is exposed on your perimeter with a free passive scan.
Free scan