# CVE-2016-2568: Privilege escalation in n/a

> Local attackers can escalate privileges to the parent session by exploiting a TIOCSTI ioctl vulnerability in the pkexec utility.

- **Severity:** High 7.8 (`CVSS:3.1/AV:L/AC:H/PR:L/UI:N/S:C/C:H/I:H/A:H`)
- **Exploited in the wild:** Not known
- **Login needed:** Any signed-in user
- **Attackable:** Local or same network only
- **Victim action needed:** Not needed
- **Fix available:** Yes
- **Published:** 13 Feb 2017
- **Updated:** 8 Oct 2026
- **Also known as:** AZL-35109, AZL-6800, DEBIAN-CVE-2016-2568, GHSA-8vgc-x7hv-3g84, UBUNTU-CVE-2016-2568

## What is CVE-2016-2568?

CVE-2016-2568 is a high-severity vulnerability in Redhat Enterprise Linux, published on 13 Feb 2017. It can only be exploited from the same machine or local network, with no action from the victim.

### Official description

pkexec, when used with --user nonpriv, allows local users to escape to the parent session via a crafted TIOCSTI ioctl call, which pushes characters to the terminal's input buffer.

Weakness: CWE-116 (Improper Encoding or Escaping of Output)

## Which versions are affected by CVE-2016-2568?

It affects 2 products.


Products: Freedesktop Polkit, Redhat Enterprise Linux.

## How do I fix CVE-2016-2568?

Apply the vendor's patch.

## Is CVE-2016-2568 being exploited?

There is no known exploitation of CVE-2016-2568 in the wild and no public exploit code.

## Other vulnerabilities in Redhat Enterprise Linux

- [CVE-2026-4897](https://insights.sbomify.com/CVE-2026-4897/): Polkit: polkit: denial of service via unbounded input processing through standard input (medium 5.5)

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2016-2568 and fix it if it is affected.

What it is: CVE-2016-2568 is a high-severity vulnerability in Redhat Enterprise Linux, published on 13 Feb 2017. It can only be exploited from the same machine or local network, with no action from the victim.
Exploitation: There is no known exploitation of CVE-2016-2568 in the wild and no public exploit code.

Affected product: Redhat Enterprise Linux. No package-level version data is available, so check the vendor advisory linked from the reference page.

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-2016-2568/ (Markdown: https://insights.sbomify.com/CVE-2016-2568/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2016-2568
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2016-2568
- OSV: https://osv.dev/vulnerability/CVE-2016-2568

---
From sbomify Insights: https://insights.sbomify.com/CVE-2016-2568/
Summaries are generated and may contain mistakes; the official description above is the record.