# CVE-2016-10027: Smack allows the bypass of TLS protections

> Man-in-the-middle attackers can bypass TLS protections and force cleartext authentication in Smack XMPP library when SecurityMode.required is set.

- **Severity:** Medium 5.9 (`CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:N/A:N`)
- **Exploited in the wild:** Not known
- **Login needed:** Not needed
- **Attackable:** Over the internet
- **Victim action needed:** Not needed
- **Fix available:** Yes
- **Published:** 12 Jan 2017
- **Updated:** 6 Aug 2024
- **Also known as:** GHSA-66pq-hqv5-228g

## What is CVE-2016-10027?

CVE-2016-10027 is a medium-severity vulnerability in Fedoraproject Fedora, published on 12 Jan 2017. An attacker can exploit it over the internet without logging in, with no action from the victim.

### Official 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.

Weakness: CWE-362 (Concurrent Execution using Shared Resource with Improper Synchronization)

## Which versions are affected by CVE-2016-10027?

2 open source packages ship an affected version, including org.igniterealtime.smack:smack-core. It affects 2 products.


| Package | Ecosystem | Affected | Fixed in |
| --- | --- | --- | --- |
| `org.igniterealtime.smack:smack-core` | Maven | All versions | 4.1.9 |
| `org.igniterealtime.smack:smack-core` | Maven | All versions | 4.1.9 |

Products: Fedoraproject Fedora, Igniterealtime Smack.

## How do I fix CVE-2016-10027?

Upgrade org.igniterealtime.smack:smack-core to 4.1.9 or later.

## Is CVE-2016-10027 being exploited?

There is no known exploitation of CVE-2016-10027 in the wild and no public exploit code.

## Other vulnerabilities in Fedoraproject Fedora

- [CVE-2024-4577](https://insights.sbomify.com/CVE-2024-4577/): PHP-CGI OS Command Injection (critical 9.8, exploited in the wild)
- [CVE-2021-39226](https://insights.sbomify.com/CVE-2021-39226/): Grafana Authentication Bypass (critical 9.8, exploited in the wild)
- [CVE-2019-5544](https://insights.sbomify.com/CVE-2019-5544/): VMware ESXi and Horizon DaaS OpenSLP Heap-Based Buffer Overflow (critical 9.8, exploited in the wild)
- [CVE-2024-4947](https://insights.sbomify.com/CVE-2024-4947/): Google Chromium V8 Type Confusion (critical 9.6, exploited in the wild)
- [CVE-2024-4671](https://insights.sbomify.com/CVE-2024-4671/): Google Chromium Visuals Use-After-Free (critical 9.6, exploited in the wild)

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2016-10027 and fix it if it is affected.

What it is: CVE-2016-10027 is a medium-severity vulnerability in Fedoraproject Fedora, published on 12 Jan 2017. An attacker can exploit it over the internet without logging in, with no action from the victim.
Exploitation: There is no known exploitation of CVE-2016-10027 in the wild and no public exploit code.

Affected packages and fixed versions:
- org.igniterealtime.smack:smack-core (Maven): affected all versions; fixed in 4.1.9
- org.igniterealtime.smack:smack-core (Maven): affected all versions; fixed in 4.1.9

Task:
1. Search the dependency manifests and lockfiles (for example package.json, package-lock.json, requirements.txt, poetry.lock, uv.lock, pom.xml, build.gradle, go.mod, Cargo.lock, Gemfile.lock) and any Dockerfiles for the affected packages, including transitive dependencies.
2. If an affected version is in use, upgrade it to the fixed version for its release line with the project's package manager, so the lockfile is regenerated. Prefer the smallest upgrade that fixes it.
3. If there is no fix, or the upgrade would break the build, do not guess: explain the risk and the safest workaround instead.
4. Run the tests and summarise what changed and why.
5. If nothing in the project is affected, say so and change nothing.

Reference: https://insights.sbomify.com/CVE-2016-10027/ (Markdown: https://insights.sbomify.com/CVE-2016-10027/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2016-10027
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2016-10027
- OSV: https://osv.dev/vulnerability/CVE-2016-10027

---
From sbomify Insights: https://insights.sbomify.com/CVE-2016-10027/
Summaries are generated and may contain mistakes; the official description above is the record.