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OpenAdvisories
High ALAS2-2025-2859 3 CVEs

Important: thunderbird security update (Amazon Linux 2)

Published May 21, 2025 · Updated Jun 24, 2025

Summary

Package updates are available for Amazon Linux 2 that fix the following vulnerabilities: CVE-2025-3932: 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. This vulnerability affects Thunderbird < 128.10.1 and Thunderbird < 138.0.1. CVE-2025-3909: Thunderbird's handling of the X-Mozilla-External-Attachment-URL header can be exploited to execute JavaScript in the file:/// context. By crafting a nested email attachment (message/rfc822) and setting its content type to application/pdf, Thunderbird may incorrectly render it as HTML when opened, allowing the embedded JavaScript to run without requiring a file download. This behavior relies on Thunderbird auto-saving the attachment to /tmp and linking to it via the file:/// protocol, potentially enabling JavaScript execution as part of the HTML. This vulnerability affects Thunderbird < 128.10.1 and Thunderbird < 138.0.1. CVE-2025-3875: Thunderbird parses addresses in a way that can allow sender spoofing in case the server allows an invalid From address to be used. For example, if the From header contains an (invalid) value "Spoofed Name ", Thunderbird treats spoofed@example.com as the actual address. This vulnerability affects Thunderbird < 128.10.1 and Thunderbird < 138.0.1.

Fixed packages 2

ReleasePackageFixed in
Amazon Linux · 2 thunderbird 0:128.10.1-1.amzn2.0.1
Amazon Linux · 2 thunderbird-debuginfo 0:128.10.1-1.amzn2.0.1

Vulnerabilities 3

  • High 8.1

    JavaScript Execution via Spoofed PDF Attachment and file:/// Link

    Thunderbird's handling of the X-Mozilla-External-Attachment-URL header can be exploited to execute JavaScript in the file:/// context. By crafting a nested email attachment (message/rfc822) and setting its content type to application/pdf, Thunderbird may inco…

  • High 7.5

    Sender Spoofing via Malformed From Header in Thunderbird

    Thunderbird parses addresses in a way that can allow sender spoofing in case the server allows an invalid From address to be used. For example, if the From header contains an (invalid) value "Spoofed Name ", Thunderbird treats spoofed@example.com as the actua…

  • Medium 6.5

    Tracking Links in Attachments Bypassed Remote Content Blocking

    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 fix…

References

  • web
    https://alas.aws.amazon.com/cve/html/CVE-2025-3875.html
  • web
    https://alas.aws.amazon.com/cve/html/CVE-2025-3909.html
  • web
    https://alas.aws.amazon.com/cve/html/CVE-2025-3932.html