CVE-2025-4091: Memory safety bugs fixed in Firefox 138, Thunderbird 138, Firefox ESR 128.10, and Thunderbird 128.10

Published Apr 29, 2025
·
Updated

Memory safety bugs present in Firefox 137, Thunderbird 137, Firefox ESR 128.9, and Thunderbird 128.9. 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 138, Firefox ESR 128.10, Thunderbird 138, and Thunderbird 128.10.

Other sources

Memory safety bugs present in Firefox 137, Thunderbird 137, Firefox ESR 128.9, and Thunderbird 128.9. 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 affects Firefox < 138, Firefox ESR < 128.10, Thunderbird < 138, and Thunderbird ESR < 128.10.

— Red Hat

Affected Software

25 affected componentsFixes available
Mozilla Firefox<138
Mozilla Firefox ESR<128.10
Mozilla Thunderbird<138
Mozilla Thunderbird ESR<128.10
Mozilla Thunderbird<138
138
Mozilla Firefox<128.10
Mozilla Firefox<138.0
Mozilla Thunderbird<128.10.0
Mozilla Thunderbird<138.0
ubuntu/mozjs52*
ubuntu/mozjs38*
ubuntu/mozjs68*
ubuntu/mozjs52*
ubuntu/mozjs102*
ubuntu/mozjs78*
ubuntu/mozjs91*
ubuntu/thunderbird<1:128.12.0+build1-0ubuntu0.22.04.1
1:128.12.0+build1-0ubuntu0.22.04.1
ubuntu/mozjs102*
ubuntu/mozjs115*
Mozilla Firefox<138
138
Mozilla Firefox ESR<128.10
128.10
Mozilla Thunderbird<128.10
128.10
debian/firefox
160.0-1
debian/firefox-esr
140.12.0esr-1~deb12u1153.7.0esr-1~deb12u1140.15.0esr-1~deb13u1153.6.0esr-1~deb13u1153.5.1esr-1153.7.0esr-1
debian/thunderbird
1:140.12.0esr-1~deb12u11:153.6.0esr-1~deb12u21:140.12.0esr-1~deb13u11:153.6.0esr-1~deb13u11:153.5.0esr-11:153.7.0esr-1

Remediation

Recommended actions to resolve this vulnerability, in priority order.

  1. Upgrade

    Upgrade Thunderbird to a version that resolves this vulnerability.

    Fixed in 138
  2. Upgrade

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

    Fixed in 1:128.12.0+build1-0ubuntu0.22.04.1
  3. Upgrade

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

    Fixed in 138
  4. Upgrade

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

    Fixed in 128.10
  5. Upgrade

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

    Fixed in 160.0-1
  6. Upgrade

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

    Fixed in 140.12.0esr-1~deb12u1Fixed in 153.7.0esr-1~deb12u1Fixed in 140.15.0esr-1~deb13u1Fixed in 153.6.0esr-1~deb13u1Fixed in 153.5.1esr-1Fixed in 153.7.0esr-1
  7. Upgrade

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

    Fixed in 1:140.12.0esr-1~deb12u1Fixed in 1:153.6.0esr-1~deb12u2Fixed in 1:140.12.0esr-1~deb13u1Fixed in 1:153.6.0esr-1~deb13u1Fixed in 1:153.5.0esr-1Fixed in 1:153.7.0esr-1
  8. Upgrade

    Upgrade Firefox to a version that resolves this vulnerability.

    Fixed in 138
  9. Upgrade

    Upgrade Firefox ESR to a version that resolves this vulnerability.

    Fixed in 128.10
  10. Upgrade

    Upgrade Thunderbird ESR to a version that resolves this vulnerability.

    Fixed in 128.10

Event History

Apr 29, 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·01:13 PM
Data Sourced
via MITRE·01:13 PM
Description
Data Sourced
via Red Hat·02:01 PM
DescriptionSeverityAffected Software
Data Sourced
via OSV·02:15 PM
DescriptionSeverityAffected Software
Data Sourced
via NVD·02:15 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-2025-4091?

CVE-2025-4091 has been classified as a memory safety vulnerability that could potentially allow the execution of arbitrary code.

2

How do I fix CVE-2025-4091?

To resolve CVE-2025-4091, update Firefox to version 138 or newer, and Thunderbird to version 139 or newer.

3

What software is affected by CVE-2025-4091?

CVE-2025-4091 affects Mozilla Firefox versions below 138, Firefox ESR versions below 128.10, and Thunderbird versions below 138.

4

What types of bugs are associated with CVE-2025-4091?

CVE-2025-4091 is associated with memory safety bugs that exhibit evidence of memory corruption.

5

Can CVE-2025-4091 be exploited?

While CVE-2025-4091 shows potential for exploitation, it requires significant effort to achieve arbitrary code execution.

Company

Resources

Contact

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