CVE-2026-75874: Sandbox escape in the Remote Settings Client component

Published Aug 18, 2026
·
Updated

Sandbox escape in the Remote Settings Client component. This vulnerability was fixed in Firefox 154, Thunderbird 154, Firefox ESR 115.40, Firefox ESR 140.15, Firefox ESR 153.2, Thunderbird 140.15, and Thunderbird 153.2.

Affected Software

10 affected componentsFixes available
Mozilla Firefox<154
Mozilla Firefox<154
154
Mozilla Thunderbird<154
154
Mozilla Firefox ESR<140.15
140.15
Mozilla Firefox ESR<115.40
115.40
Mozilla Firefox ESR<153.2
153.2
Mozilla Firefox<154.0.0
Mozilla Thunderbird<154.0
Mozilla Thunderbird<140.15
140.15
Mozilla Thunderbird<153.2
153.2

Remediation

Recommended actions to resolve this vulnerability, in priority order.

  1. Upgrade

    Upgrade to a fixed release to a version that resolves this vulnerability.

    Fixed in 154
  2. Upgrade

    Upgrade to a fixed release to a version that resolves this vulnerability.

    Fixed in 140.15
  3. Upgrade

    Upgrade to a fixed release to a version that resolves this vulnerability.

    Fixed in 115.40
  4. Upgrade

    Upgrade to a fixed release to a version that resolves this vulnerability.

    Fixed in 153.2
  5. Upgrade

    Upgrade Mozilla Firefox / Thunderbird (Remote Settings Client) to a version that resolves this vulnerability.

    Fixed in 154
  6. Upgrade

    Upgrade Mozilla Firefox ESR / Thunderbird ESR (Remote Settings Client) to a version that resolves this vulnerability.

    Fixed in 115.40
  7. Upgrade

    Upgrade Mozilla Firefox ESR / Thunderbird ESR (Remote Settings Client) to a version that resolves this vulnerability.

    Fixed in 140.15
  8. Upgrade

    Upgrade Mozilla Firefox ESR / Thunderbird ESR (Remote Settings Client) to a version that resolves this vulnerability.

    Fixed in 153.2

Event History

Aug 18, 2026
CVE Published
via Mozilla·12:00 AM
Data Sourced
via Mozilla·12:00 AM
DescriptionSeverityAffected Software
Updated
via Mozilla·12:00 AM
Affected Software
CVE Published
via MITRE·12:23 PM
Data Sourced
via MITRE·12:23 PM
Description
Data Sourced
via NVD·01:17 PM
DescriptionSeverityWeaknessAffected Software
Sep 1, 2026
Updated
via Mozilla·12:00 AM
Affected Software

Parent advisories

This vulnerability appears in the following advisories.

Peer vulnerabilities

Found alongside the following vulnerabilities.

Frequently Asked Questions

1

Which Firefox release contains the fix?

The issue is fixed in Firefox 154. The provided information does not identify affected earlier versions, platforms, or configurations.

2

What is required to exploit this issue, and is there a mitigation short of upgrading?

The provided information only identifies the issue as a sandbox escape in the Remote Settings Client component. It does not state the required attacker access, exploitation conditions, or any workaround for unpatched installations.

Company

Resources

Contact

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