CVE-2026-16412: Memory safety bugs fixed in Thunderbird ESR 140.13 and Thunderbird 153

Published Jul 21, 2026
·
Updated

Memory safety bugs present in Firefox ESR 140.12 and Firefox 152. Some of these bugs showed evidence of memory corruption and we presume that with enough effort some of these could have been exploited to run arbitrary code.

Other sources

Memory safety bugs present in Thunderbird ESR 140.12 and Thunderbird 152. Some of these bugs showed evidence of memory corruption and we presume that with enough effort some of these could have been exploited to run arbitrary code.

— Mozilla

Affected Software

7 affected componentsFixes available
Mozilla Firefox>140.12<140.13, >152<153
Mozilla Firefox<153
153
Mozilla Firefox ESR<140.13
140.13
Mozilla Firefox<153.0.0
Mozilla Firefox>=140.1.0<140.13.0
Mozilla Thunderbird<140.13
140.13
Mozilla Thunderbird<153
153

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 153
  2. Upgrade

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

    Fixed in 140.13
  3. Upgrade

    Upgrade Firefox ESR to a version that resolves this vulnerability.

    Fixed in 140.13
  4. Upgrade

    Upgrade Firefox to a version that resolves this vulnerability.

    Fixed in 153
  5. Upgrade

    Upgrade Thunderbird ESR to a version that resolves this vulnerability.

    Fixed in 140.13
  6. Upgrade

    Upgrade Thunderbird to a version that resolves this vulnerability.

    Fixed in 153

Event History

Jul 21, 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
Updated
via Mozilla·12:00 AM
DescriptionAffected Software
CVE Published
via MITRE·12:38 PM
Data Sourced
via MITRE·12:38 PM
Description
Data Sourced
via NVD·01:17 PM
DescriptionSeverityWeaknessAffected Software

Parent advisories

This vulnerability appears in the following advisories.

Peer vulnerabilities

Found alongside the following vulnerabilities.

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Frequently Asked Questions

1

What is the severity of CVE-2026-16412?

CVE-2026-16412 has a critical severity rating of 9.8 according to the CVSS 3.1 score.

2

How do I fix CVE-2026-16412?

To fix CVE-2026-16412, users should upgrade to Thunderbird ESR 140.13 or Thunderbird 153.

3

What type of vulnerability is CVE-2026-16412?

CVE-2026-16412 is classified as a memory safety bug that could potentially lead to memory corruption and arbitrary code execution.

4

Which software is affected by CVE-2026-16412?

The affected software includes Mozilla Firefox ESR 140.12, Firefox 152, and their respective derivatives.

5

When was CVE-2026-16412 published?

CVE-2026-16412 was published on July 21, 2026.

Company

Resources

Contact

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