CVE-2026-16361: Memory safety bugs fixed in Thunderbird ESR 140.13

Published Jul 21, 2026
·
Updated

Memory safety bugs present in Firefox ESR 115.37 and Firefox ESR 140.12. 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. 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 ESR>115.37<=115.37, >140.12<=140.12
Mozilla Firefox ESR<115.38
115.38
Mozilla Firefox ESR<140.13
140.13
Mozilla Thunderbird<140.13
140.13
Mozilla Firefox<115.38.0
Mozilla Firefox>=128.1.0<140.13.0
Mozilla Thunderbird<140.13.0

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 115.38
  2. Upgrade

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

    Fixed in 140.13
  3. Upgrade

    Upgrade Mozilla Firefox ESR to a version that resolves this vulnerability.

    Fixed in 115.38
  4. Upgrade

    Upgrade Mozilla Firefox ESR to a version that resolves this vulnerability.

    Fixed in 140.13
  5. Upgrade

    Upgrade Mozilla Thunderbird ESR to a version that resolves this vulnerability.

    Fixed in 140.13

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-2026-16361?

CVE-2026-16361 has a critical severity rating of 9.8 according to the CVSS 3.1 metrics.

2

How do I fix CVE-2026-16361?

To fix CVE-2026-16361, users should update to Firefox ESR version 115.38 or 140.13.

3

What types of vulnerabilities are associated with CVE-2026-16361?

CVE-2026-16361 is associated with memory safety bugs, specifically memory corruption and potential buffer overflow vulnerabilities.

4

What software is affected by CVE-2026-16361?

CVE-2026-16361 affects Mozilla Firefox ESR versions 115.37 and 140.12, as well as Mozilla Thunderbird.

5

Can CVE-2026-16361 be exploited to run arbitrary code?

Yes, while exploiting CVE-2026-16361 may require significant effort, some memory safety bugs could potentially allow for arbitrary code execution.

Company

Resources

Contact

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