CVE-2025-3932: Tracking Links in Attachments Bypassed Remote Content Blocking

Published May 13, 2025
·
Updated

It was possible to craft an email that showed a tracking link as an attachment. If the user attempted to open the attachment, Thunderbird automatically accessed the link. The configuration to block remote content did not prevent that. Thunderbird has been fixed to no longer allow access to web pages listed in the X-Mozilla-External-Attachment-URL header of an email.

Affected Software

7 affected componentsFixes available
Mozilla Thunderbird<128.10.1, <138.0.1
Mozilla Thunderbird<138.0.1
138.0.1
Mozilla Thunderbird<128.10.1
Mozilla Thunderbird>=129.0<138.0.1
ubuntu/thunderbird<1:128.12.0+build1-0ubuntu0.22.04.1
1:128.12.0+build1-0ubuntu0.22.04.1
Mozilla Thunderbird<128.10.1
128.10.1
debian/thunderbird
1:140.12.0esr-1~deb12u11:153.7.0esr-1~deb12u11:140.12.0esr-1~deb13u11:153.7.0esr-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 138.0.1
  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 128.10.1
  4. Upgrade

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

    Fixed in 1:140.12.0esr-1~deb12u1Fixed in 1:153.7.0esr-1~deb12u1Fixed in 1:140.12.0esr-1~deb13u1Fixed in 1:153.7.0esr-1~deb13u1Fixed in 1:153.5.0esr-1Fixed in 1:153.7.0esr-1
  5. Upgrade

    Upgrade Thunderbird to a version that resolves this vulnerability.

    Fixed in 128.10.1

Event History

May 13, 2025
CVE Published
via Mozilla·12:00 AM
Data Sourced
via Mozilla·12:00 AM
DescriptionSeverityAffected Software
May 14, 2025
Data Sourced
via Ubuntu·12:00 AM
RemedyDescriptionSeverityAffected Software
CVE Published
via MITRE·04:56 PM
Data Sourced
via MITRE·04:56 PM
Description
Data Sourced
via OSV·05:15 PM
DescriptionSeverityAffected Software
Data Sourced
via NVD·05:15 PM
DescriptionSeverityWeaknessAffected Software
Data Sourced
via Red Hat·06:02 PM
DescriptionSeverityAffected 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-2025-3932?

CVE-2025-3932 is considered a high severity vulnerability that could lead to unauthorized access to tracking links.

2

How do I fix CVE-2025-3932?

To mitigate CVE-2025-3932, users should update Thunderbird to version 138.0.1 or 128.10.1.

3

Which versions of Thunderbird are affected by CVE-2025-3932?

CVE-2025-3932 affects Thunderbird versions prior to 138.0.1 and 128.10.1.

4

What is the impact of CVE-2025-3932 on Thunderbird users?

Users of Thunderbird are at risk of being redirected to malicious web pages when opening crafted email attachments.

5

Is there a workaround for CVE-2025-3932?

There are no effective workarounds for CVE-2025-3932; the recommended action is to update to the latest version.

Company

Resources

Contact

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