# CVE-2018-5108: Information disclosure in Firefox

> Attackers can leak private browsing data to normal tabs via Blob URLs if users manually enter the URL, affecting Firefox users.

- **Severity:** Medium 4.3 (`CVSS:3.0/AV:N/AC:L/PR:N/UI:R/S:U/C:L/I:N/A:N`)
- **Exploited in the wild:** Not known
- **Login needed:** Not needed
- **Attackable:** Over the internet
- **Victim action needed:** A user has to click or open something
- **Fix available:** Yes
- **Published:** 11 Jun 2018
- **Updated:** 5 Aug 2024
- **Also known as:** GHSA-9fmf-gjw2-hq6p, UBUNTU-CVE-2018-5108

## What is CVE-2018-5108?

CVE-2018-5108 is a medium-severity vulnerability in Canonical Ubuntu Linux, published on 11 Jun 2018. An attacker can exploit it over the internet without logging in, and only if a user opens a file or follows a link.

### Official description

A Blob URL can violate origin attribute segregation, allowing it to be accessed from a private browsing tab and for data to be passed between the private browsing tab and a normal tab. This could allow for the leaking of private information specific to the private browsing context. This issue is mitigated by the requirement that the user enter the Blob URL manually in order for the access violation to occur. This vulnerability affects Firefox < 58.

Weakness: CWE-200 (Exposure of Sensitive Information to an Unauthorized Actor)

## Which versions are affected by CVE-2018-5108?

It affects 2 products.


Products: Canonical Ubuntu Linux, Mozilla Firefox.

## How do I fix CVE-2018-5108?

Upgrade to a fixed version.

## Is CVE-2018-5108 being exploited?

There is no known exploitation of CVE-2018-5108 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-2018-5108 and fix it if it is affected.

What it is: CVE-2018-5108 is a medium-severity vulnerability in Canonical Ubuntu Linux, published on 11 Jun 2018. An attacker can exploit it over the internet without logging in, and only if a user opens a file or follows a link.
Exploitation: There is no known exploitation of CVE-2018-5108 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-2018-5108/ (Markdown: https://insights.sbomify.com/CVE-2018-5108/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2018-5108
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2018-5108
- OSV: https://osv.dev/vulnerability/CVE-2018-5108

---
From sbomify Insights: https://insights.sbomify.com/CVE-2018-5108/
Summaries are generated and may contain mistakes; the official description above is the record.