CVE-2025-9185: Memory safety bugs fixed in Firefox ESR 115.27, Firefox ESR 128.14, Thunderbird ESR 128.14, Firefox ESR 140.2, Thunderbird ESR 140.2, Firefox 142 and Thunderbird 142

Published Aug 19, 2025
·
Updated

Memory safety bugs present in Firefox ESR 115.26, Firefox ESR 128.13, Thunderbird ESR 128.13, Firefox ESR 140.1, Thunderbird ESR 140.1, Firefox 141 and Thunderbird 141. 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 142, Firefox ESR 115.27, Firefox ESR 128.14, Firefox ESR 140.2, Thunderbird 142, Thunderbird 128.14, and Thunderbird 140.2.

Other sources

Memory safety bugs present in Firefox ESR 115.26, Firefox ESR 128.13, Thunderbird ESR 128.13, Firefox ESR 140.1, Thunderbird ESR 140.1, Firefox 141 and Thunderbird 141. 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 < 142, Firefox ESR < 115.27, Firefox ESR < 128.14, Firefox ESR < 140.2, Thunderbird < 142, Thunderbird < 128.14, and Thunderbird < 140.2.

— Red Hat

Affected Software

30 affected componentsFixes available
Mozilla Firefox<142
Mozilla Firefox ESR<115.27, <128.14, <140.2
Mozilla Thunderbird<142, <128.14, <140.2
Mozilla Thunderbird<142
142
Mozilla Firefox ESR<115.27
115.27
Mozilla Thunderbird<140.2
140.2
Mozilla Firefox ESR<140.2
140.2
Mozilla Firefox<115.27.0
Mozilla Firefox<142.0
Mozilla Firefox>=128.0<128.14.0
Mozilla Firefox>=140.0<140.2.0
Mozilla Thunderbird<128.14.0
Mozilla Thunderbird<142.0
Mozilla Thunderbird>=140.0<140.2.0
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<142
142
Mozilla Firefox ESR<128.14
128.14
Mozilla Thunderbird<128.14
128.14
debian/firefox
159.0-1
debian/firefox-esr
140.12.0esr-1~deb12u1153.6.0esr-1~deb12u2140.15.0esr-1~deb13u1153.6.0esr-1~deb13u1153.5.1esr-1153.6.0esr-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-11:153.6.0esr-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 142
  2. Upgrade

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

    Fixed in 115.27
  3. Upgrade

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

    Fixed in 140.2
  4. Upgrade

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

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

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

    Fixed in 128.14
  6. Upgrade

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

    Fixed in 159.0-1
  7. Upgrade

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

    Fixed in 140.12.0esr-1~deb12u1Fixed in 153.6.0esr-1~deb12u2Fixed in 140.15.0esr-1~deb13u1Fixed in 153.6.0esr-1~deb13u1Fixed in 153.5.1esr-1Fixed in 153.6.0esr-1
  8. 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~deb12u1Fixed in 1:140.12.0esr-1~deb13u1Fixed in 1:153.6.0esr-1~deb13u1Fixed in 1:153.5.0esr-1Fixed in 1:153.6.0esr-1
  9. Upgrade

    Upgrade Firefox to a version that resolves this vulnerability.

    Fixed in 142
  10. Upgrade

    Upgrade Firefox ESR to a version that resolves this vulnerability.

    Fixed in 115.27
  11. Upgrade

    Upgrade Firefox ESR to a version that resolves this vulnerability.

    Fixed in 128.14
  12. Upgrade

    Upgrade Firefox ESR to a version that resolves this vulnerability.

    Fixed in 140.2
  13. Upgrade

    Upgrade Thunderbird to a version that resolves this vulnerability.

    Fixed in 142
  14. Upgrade

    Upgrade Thunderbird ESR to a version that resolves this vulnerability.

    Fixed in 128.14
  15. Upgrade

    Upgrade Thunderbird ESR to a version that resolves this vulnerability.

    Fixed in 140.2

Event History

Aug 19, 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·08:33 PM
Data Sourced
via MITRE·08:33 PM
Description
Data Sourced
via Red Hat·09:02 PM
DescriptionSeverityAffected Software
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-2025-9185?

CVE-2025-9185 is classified as a high severity vulnerability due to its potential for memory corruption exploitation.

2

How do I fix CVE-2025-9185?

To fix CVE-2025-9185, users should update to the latest version of Mozilla Firefox or Thunderbird where the vulnerability has been patched.

3

Which versions of Firefox are affected by CVE-2025-9185?

CVE-2025-9185 affects Firefox versions up to 142 and Firefox ESR versions up to 115.27, 128.14, and 140.2.

4

Which versions of Thunderbird are susceptible to CVE-2025-9185?

CVE-2025-9185 affects Thunderbird versions up to 142 and Thunderbird ESR versions up to 128.14 and 140.2.

5

What are the potential impacts of CVE-2025-9185?

The potential impacts of CVE-2025-9185 include unauthorized access to sensitive data and possible system compromise due to memory safety issues.

Company

Resources

Contact

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