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

What is CVE-2020-5423?

CVE-2020-5423 is a high-severity denial of service vulnerability in Cloud Foundry CAPI, published on 2 Dec 2020. An attacker can exploit it over the internet without logging in, with no action from the victim.

Official 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.

Weakness: CWE-400

Which versions are affected by CVE-2020-5423?

It affects 2 products.

Products include Cloudfoundry Capi-Release, Cloudfoundry Cf-Deployment.

How do I fix CVE-2020-5423?

No fix has been published for CVE-2020-5423 yet. Limit exposure of the affected software until one is available.

Upgrade, then put limits on request size, rate and nesting depth so one client cannot exhaust the service. More about Denial of service.

Is CVE-2020-5423 being exploited?

There is no known exploitation of CVE-2020-5423 in the wild and no public exploit code.

Other vulnerabilities in Cloud Foundry CAPI

• CVE-2018-1195 Auth bypass in Cloud Controller High 8.8
• CVE-2020-5417 Cloud Controller may allow developers to claim sensitive routes High 8.5
• CVE-2023-20881 Missing authorization in Cloud Controller API High 8.1
• CVE-2018-1266 Path traversal in n/a High 8.1
• CVE-2020-5400 Cloud Controller logs environment variables from app manifests High 8.0

Sources

• CVE record
• NVD
• OSV
• GitHub advisory
• How this page is made

Also known as GHSA-jj4c-53qh-fp5v.