# CVE-2018-18505: Auth bypass in Firefox

> Insufficient IPC authentication allows sandbox escape via message validation flaws, enabling code execution and privilege escalation in Firefox and Thunderbird.

- **Severity:** Critical 10.0 (`CVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:C/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:** Yes
- **Published:** 5 Feb 2019
- **Updated:** 5 Aug 2024
- **Also known as:** DEBIAN-CVE-2018-18505, GHSA-5g4g-56fq-mvwf, UBUNTU-CVE-2018-18505

## What is CVE-2018-18505?

CVE-2018-18505 is a critical authentication bypass vulnerability in Canonical Ubuntu Linux, published on 5 Feb 2019. An attacker can exploit it over the internet without logging in, with no action from the victim.

### Official description

An earlier fix for an Inter-process Communication (IPC) vulnerability, CVE-2011-3079, added authentication to communication between IPC endpoints and server parents during IPC process creation. This authentication is insufficient for channels created after the IPC process is started, leading to the authentication not being correctly applied to later channels. This could allow for a sandbox escape through IPC channels due to lack of message validation in the listener process. This vulnerability affects Thunderbird < 60.5, Firefox ESR < 60.5, and Firefox < 65.

Weakness: CWE-287 (Improper Authentication)

## Which versions are affected by CVE-2018-18505?

It affects 10 products.


Products: Canonical Ubuntu Linux, Debian Debian Linux, Mozilla Firefox, Mozilla Thunderbird, Redhat Enterprise Linux Desktop, Redhat Enterprise Linux Server, Redhat Enterprise Linux Server Aus, Redhat Enterprise Linux Server Eus, Redhat Enterprise Linux Server Tus, Redhat Enterprise Linux Workstation.

## How do I fix CVE-2018-18505?

Upgrade to a fixed version.

## Is CVE-2018-18505 being exploited?

There is no known exploitation of CVE-2018-18505 in the wild and no public exploit code.

## Other vulnerabilities in Canonical Ubuntu Linux

- [CVE-2020-11651](https://insights.sbomify.com/CVE-2020-11651/): SaltStack Salt Authentication Bypass (critical 9.8, exploited in the wild)
- [CVE-2020-7247](https://insights.sbomify.com/CVE-2020-7247/): OpenSMTPD Remote Code Execution (critical 9.8, exploited in the wild)
- [CVE-2019-16928](https://insights.sbomify.com/CVE-2019-16928/): Exim Out-of-bounds Write (critical 9.8, exploited in the wild)
- [CVE-2018-6789](https://insights.sbomify.com/CVE-2018-6789/): Exim Buffer Overflow (critical 9.8, exploited in the wild)
- [CVE-2015-2590](https://insights.sbomify.com/CVE-2015-2590/): Oracle Java SE and Java SE Embedded Remote Code Execution (critical 9.8, exploited in the wild)

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2018-18505 and fix it if it is affected.

What it is: CVE-2018-18505 is a critical authentication bypass vulnerability in Canonical Ubuntu Linux, published on 5 Feb 2019. 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-2018-18505 in the wild and no public exploit code.

Affected product: Canonical Ubuntu 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-2018-18505/ (Markdown: https://insights.sbomify.com/CVE-2018-18505/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2018-18505
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2018-18505
- OSV: https://osv.dev/vulnerability/CVE-2018-18505

---
From sbomify Insights: https://insights.sbomify.com/CVE-2018-18505/
Summaries are generated and may contain mistakes; the official description above is the record.