CVE-2025-8040: Memory safety bugs fixed in Firefox ESR 140.1, Thunderbird ESR 140.1, Firefox 141 and Thunderbird 141

Published Jul 22, 2025
·
Updated

Memory safety bugs present in Firefox ESR 140.0, Thunderbird ESR 140.0, Firefox 140 and Thunderbird 140. 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. This vulnerability was fixed in Firefox 141, Firefox ESR 140.1, Thunderbird 141, and Thunderbird 140.1.

Affected Software

19 affected componentsFixes available
Mozilla Thunderbird<140.1
140.1
Mozilla Firefox ESR<140.1
140.1
Mozilla Thunderbird<141
141
Mozilla Firefox<140.1
Mozilla Firefox<141.0
Mozilla Thunderbird<140.1
Mozilla Thunderbird<141.0
ubuntu/mozjs52*
ubuntu/mozjs38*
ubuntu/mozjs68*
ubuntu/mozjs52*
ubuntu/mozjs102*
ubuntu/mozjs78*
ubuntu/mozjs91*
ubuntu/thunderbird<1:140.7.1+build1-0ubuntu0.22.04.1
1:140.7.1+build1-0ubuntu0.22.04.1
ubuntu/mozjs102*
ubuntu/mozjs115*
Mozilla Firefox<141
141
debian/firefox
159.0-1

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 140.1
  2. Upgrade

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

    Fixed in 141
  3. Upgrade

    Upgrade ubuntu/thunderbird to a version that resolves this vulnerability.

    Fixed in 1:140.7.1+build1-0ubuntu0.22.04.1
  4. Upgrade

    Upgrade debian/firefox to a version that resolves this vulnerability.

    Fixed in 159.0-1
  5. Upgrade

    Upgrade Firefox ESR to a version that resolves this vulnerability.

    Fixed in 140.1
  6. Upgrade

    Upgrade Thunderbird ESR to a version that resolves this vulnerability.

    Fixed in 140.1
  7. Upgrade

    Upgrade Firefox to a version that resolves this vulnerability.

    Fixed in 141
  8. Upgrade

    Upgrade Thunderbird to a version that resolves this vulnerability.

    Fixed in 141

Event History

Jul 22, 2025
CVE Published
via Mozilla·12:00 AM
Data Sourced
via Mozilla·12:00 AM
DescriptionSeverityAffected Software
Data Sourced
via Ubuntu·12:00 AM
RemedyDescriptionSeverityAffected Software
CVE Published
via MITRE·08:49 PM
Data Sourced
via MITRE·08:49 PM
Description
Data Sourced
via OSV·09:15 PM
DescriptionSeverityAffected Software
Data Sourced
via NVD·09:15 PM
DescriptionSeverityWeaknessAffected Software

Parent advisories

This vulnerability appears in the following advisories.

Peer vulnerabilities

Found alongside the following vulnerabilities.

Frequently Asked Questions

1

What is the severity of CVE-2025-8040?

CVE-2025-8040 has a high severity due to the potential for exploitation leading to arbitrary code execution.

2

How do I fix CVE-2025-8040?

To resolve CVE-2025-8040, upgrade to Firefox version 141 or Thunderbird version 140.1.

3

What products are affected by CVE-2025-8040?

CVE-2025-8040 affects Firefox ESR 140.0, Thunderbird ESR 140.0, Firefox 140, and Thunderbird 140.

4

What types of bugs are present in CVE-2025-8040?

CVE-2025-8040 includes memory safety bugs that may lead to memory corruption.

5

Can CVE-2025-8040 be exploited remotely?

Yes, with sufficient effort, the memory corruption issues in CVE-2025-8040 could potentially be exploited to run arbitrary code.

Company

Resources

Contact

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