# CVE-2023-45239: Command injection in tac plus

> Attackers can inject shell commands via controlled username or address fields in tac_plus when pre/post auth commands are enabled, leading to remote code execution.

- **Severity:** Critical 9.8 (`CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H`)
- **Exploited in the wild:** Not known
- **Login needed:** Not needed
- **Attackable:** Over the internet
- **Victim action needed:** Not needed
- **Fix available:** No
- **Published:** 6 Oct 2023
- **Updated:** 13 Feb 2025
- **Also known as:** GHSA-p334-5r3g-4vx3

## What is CVE-2023-45239?

CVE-2023-45239 is a critical command injection vulnerability in Fedoraproject Fedora, published on 6 Oct 2023. An attacker can exploit it over the internet without logging in, with no action from the victim.

### Official description

A lack of input validation exists in tac_plus prior to commit 4fdf178 which, when pre or post auth commands are enabled, allows an attacker who can control the username, rem-addr, or NAC address sent to tac_plus to inject shell commands and gain remote code execution on the tac_plus server.

Weakness: CWE-790 (Improper Filtering of Special Elements)

## Which versions are affected by CVE-2023-45239?

It affects 2 products.


Products: Facebook Tac Plus, Fedoraproject Fedora.

## How do I fix CVE-2023-45239?

No fix has been published for CVE-2023-45239 yet. Limit exposure of the affected software until one is available.

## Is CVE-2023-45239 being exploited?

There is no known exploitation of CVE-2023-45239 in the wild and no public exploit code.

Public exploit code:

- tac_plus Pre-Auth Remote Command Execution Vulnerability (CVE-2023-45239 & CVE-2023-48643) (github_poc): https://github.com/takeshixx/tac_plus-pre-auth-rce

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2023-45239 and fix it if it is affected.

What it is: CVE-2023-45239 is a critical command injection vulnerability in Fedoraproject Fedora, published on 6 Oct 2023. 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-2023-45239 in the wild and no public exploit code.

Affected product: Fedoraproject Fedora. 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-2023-45239/ (Markdown: https://insights.sbomify.com/CVE-2023-45239/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2023-45239
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2023-45239
- OSV: https://osv.dev/vulnerability/CVE-2023-45239

---
From sbomify Insights: https://insights.sbomify.com/CVE-2023-45239/
Summaries are generated and may contain mistakes; the official description above is the record.