# CVE-2017-7838: Other in Firefox

> Firefox displays punycode for subdomains, enabling limited domain spoofing attacks through user confusion.

- **Severity:** Medium 5.3 (`CVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:L/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:** 11 Jun 2018
- **Updated:** 5 Aug 2024
- **Also known as:** GHSA-xg4r-c4j2-fcj4, UBUNTU-CVE-2017-7838

## What is CVE-2017-7838?

CVE-2017-7838 is a medium-severity vulnerability in Mozilla Firefox, published on 11 Jun 2018. An attacker can exploit it over the internet without logging in, with no action from the victim.

### Official description

Punycode format text will be displayed for entire qualified international domain names in some instances when a sub-domain triggers the punycode display instead of the primary domain being displayed in native script and the sub-domain only displaying as punycode. This could be used for limited spoofing attacks due to user confusion. This vulnerability affects Firefox < 57.

Weakness: CWE-20 (Improper Input Validation)

## Which versions are affected by CVE-2017-7838?

It affects 1 product.


Products: Mozilla Firefox.

## How do I fix CVE-2017-7838?

Upgrade to a fixed version.

## Is CVE-2017-7838 being exploited?

There is no known exploitation of CVE-2017-7838 in the wild and no public exploit code.

## Other vulnerabilities in Mozilla Firefox

- [CVE-2019-11708](https://insights.sbomify.com/CVE-2019-11708/): Mozilla Firefox and Thunderbird Sandbox Escape (critical 10.0, exploited in the wild)
- [CVE-2010-3765](https://insights.sbomify.com/CVE-2010-3765/): Mozilla Multiple Products Remote Code Execution (critical 9.8, exploited in the wild)
- [CVE-2022-26486](https://insights.sbomify.com/CVE-2022-26486/): Mozilla Firefox Use-After-Free (critical 9.6, exploited in the wild)
- [CVE-2022-26485](https://insights.sbomify.com/CVE-2022-26485/): Mozilla Firefox Use-After-Free (high 8.8, exploited in the wild)
- [CVE-2019-11707](https://insights.sbomify.com/CVE-2019-11707/): Mozilla Firefox and Thunderbird Type Confusion (high 8.8, exploited in the wild)

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2017-7838 and fix it if it is affected.

What it is: CVE-2017-7838 is a medium-severity vulnerability in Mozilla Firefox, published on 11 Jun 2018. 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-2017-7838 in the wild and no public exploit code.

Affected product: Mozilla Firefox. 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-2017-7838/ (Markdown: https://insights.sbomify.com/CVE-2017-7838/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2017-7838
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2017-7838
- OSV: https://osv.dev/vulnerability/CVE-2017-7838

---
From sbomify Insights: https://insights.sbomify.com/CVE-2017-7838/
Summaries are generated and may contain mistakes; the official description above is the record.