Home/CVE/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 parame
CVE

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 parame

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.

HIGH · CVSS 7.5 EPSS 0.00518
Act now
  • Public exploit or PoC is available
  • CVSS base score ≥ 7.0
Sigma rules0 YARA rules0
⬡

Weakness Classification

CWE-295Improper Certificate Validation
▤

Affected Products & Versions

10
arm mbed tls< 2.7.18
arm mbed tls>= 2.8.0 and < 2.16.9
arm mbed tls>= 2.17.0 and < 2.25.0
siemens logo\! cmr2020 firmware< 2.2
siemens logo\! cmr2040 firmware< 2.2
siemens simatic rtu3031c firmwareall versions
siemens simatic rtu3041c firmwareall versions
siemens simatic rtu3030c firmwareall versions
⚠

Public Exploits & PoCs

1
pocgithub.com · 3629github.com
▣

Scoring & Timeline

7.5
HIGH · CVSS v3.1 · cve@mitre.org
View on NVD
Attack Vector
Network Adjacent Local Physical
Attack Complexity
Low High
Privileges Required
None Low High
User Interaction
None Required
Scope
Unchanged Changed
Confidentiality
None Low High
Integrity
None Low High
Availability
None Low High
Published to NVD23 Aug 2021 · 02:15 AM
CVSS VectorCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:H/A:N
⚑

Vendor Advisories

3
msrcCVE-2020-36478
siemens-csafSSA-756638
cisa-csafcisa-csaf-csaf_files-OT-white-2021-icsa-21-257-20
🔗

References & Sources

6
Source URLs (vendor pages, mailing lists, write-ups). Exploit/PoC links are in their own section above to avoid duplication.
https://cert-portal.siemens.com/productcert/pdf/ssa-756638.pdfPatchThird Party Advisory
https://github.com/ARMmbed/mbedtls/releases/tag/v2.16.9Release NotesThird Party Advisory
https://github.com/ARMmbed/mbedtls/releases/tag/v2.25.0Release NotesThird Party Advisory
https://github.com/ARMmbed/mbedtls/releases/tag/v2.7.18Release NotesThird Party Advisory
https://lists.debian.org/debian-lts-announce/2021/11/msg00021.htmlMailing ListThird Party Advisory
https://lists.debian.org/debian-lts-announce/2022/12/msg00036.htmlMailing ListThird Party Advisory
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