CVE-2026-8975: Memory safety bugs fixed in Thunderbird 140.11 and Thunderbird 151

Published May 19, 2026
·
Updated

Memory safety bugs present in Firefox ESR 115.35, Firefox ESR 140.10 and Firefox 150. 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 140.10 and Thunderbird 150. 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

10 affected componentsFixes available
Mozilla Firefox ESR<115.36
115.36
Mozilla Firefox<151
151
Mozilla Firefox ESR<140.11
140.11
Mozilla Thunderbird<151
151
Mozilla Thunderbird<140.11
140.11
Mozilla Firefox<115.36.0
Mozilla Firefox<151.0.0
Mozilla Firefox>=140.0<140.11.0
Mozilla Thunderbird<140.11
Mozilla Thunderbird<151.0.0

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 115.36
  2. Upgrade

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

    Fixed in 151
  3. Upgrade

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

    Fixed in 140.11
  4. Upgrade

    Upgrade Firefox ESR 115 to a version that resolves this vulnerability.

    Fixed in 115.36
  5. Upgrade

    Upgrade Firefox ESR 140 to a version that resolves this vulnerability.

    Fixed in 140.11
  6. Upgrade

    Upgrade Firefox to a version that resolves this vulnerability.

    Fixed in 151
  7. Upgrade

    Upgrade Thunderbird 140 to a version that resolves this vulnerability.

    Fixed in 140.11
  8. Upgrade

    Upgrade Thunderbird to a version that resolves this vulnerability.

    Fixed in 151

Event History

May 19, 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·12:30 PM
Data Sourced
via MITRE·12:30 PM
Description
Data Sourced
via Red Hat·02:01 PM
DescriptionSeverityAffected Software
Data Sourced
via NVD·02:16 PM
DescriptionSeverityWeaknessAffected Software
Apr 28, 58520
Event
via FIRST·03:30 AM

Parent advisories

This vulnerability appears in the following advisories.

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Frequently Asked Questions

1

What is the severity of CVE-2026-8975?

CVE-2026-8975 has been classified as a high severity vulnerability due to the potential for memory corruption exploits.

2

How do I fix CVE-2026-8975?

To fix CVE-2026-8975, update to Thunderbird 140.11 or 151, or Firefox ESR 115.36, 140.11, or Firefox 151.

3

What software is affected by CVE-2026-8975?

CVE-2026-8975 affects Thunderbird versions prior to 140.11 and 151, and Firefox ESR versions prior to 115.36 and 140.11.

4

What types of vulnerabilities are associated with CVE-2026-8975?

CVE-2026-8975 is associated with memory safety bugs that could lead to memory corruption.

5

Is it possible to exploit CVE-2026-8975?

Yes, CVE-2026-8975 potentially allows for exploitation if an attacker can leverage the memory safety bugs.

Contact

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