Bug 2366283 (CVE-2025-3909)

Summary: CVE-2025-3909 thunderbird: JavaScript Execution via Spoofed PDF Attachment and file:/// Link
Product: [Other] Security Response Reporter: OSIDB Bzimport <bzimport>
Component: vulnerabilityAssignee: Product Security DevOps Team <prodsec-dev>
Status: NEW --- QA Contact:
Severity: high Docs Contact:
Priority: high    
Version: unspecifiedCC: gotiwari, jhorak, mvyas, tpopela
Target Milestone: ---Keywords: Security
Target Release: ---   
Hardware: All   
OS: Linux   
Whiteboard:
Fixed In Version: Doc Type: ---
Doc Text:
The Mozilla Foundation's Security Advisory describes the following issue: 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.
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oVirt Team: --- RHEL 7.3 requirements from Atomic Host:
Cloudforms Team: --- Target Upstream Version:
Embargoed:

Description OSIDB Bzimport 2025-05-14 18:01:33 UTC
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.

Comment 1 errata-xmlrpc 2025-05-27 10:01:06 UTC
This issue has been addressed in the following products:

  Red Hat Enterprise Linux 10

Via RHSA-2025:8196 https://access.redhat.com/errata/RHSA-2025:8196

Comment 2 errata-xmlrpc 2025-05-27 12:22:34 UTC
This issue has been addressed in the following products:

  Red Hat Enterprise Linux 9

Via RHSA-2025:8203 https://access.redhat.com/errata/RHSA-2025:8203

Comment 3 errata-xmlrpc 2025-05-29 19:29:52 UTC
This issue has been addressed in the following products:

  Red Hat Enterprise Linux 9.2 Extended Update Support

Via RHSA-2025:8326 https://access.redhat.com/errata/RHSA-2025:8326

Comment 4 errata-xmlrpc 2025-05-29 21:28:24 UTC
This issue has been addressed in the following products:

  Red Hat Enterprise Linux 9.0 Update Services for SAP Solutions

Via RHSA-2025:8324 https://access.redhat.com/errata/RHSA-2025:8324

Comment 5 errata-xmlrpc 2025-05-29 22:54:04 UTC
This issue has been addressed in the following products:

  Red Hat Enterprise Linux 9.4 Extended Update Support

Via RHSA-2025:8325 https://access.redhat.com/errata/RHSA-2025:8325

Comment 6 errata-xmlrpc 2025-06-02 17:29:00 UTC
This issue has been addressed in the following products:

  Red Hat Enterprise Linux 8.2 Advanced Update Support

Via RHSA-2025:8391 https://access.redhat.com/errata/RHSA-2025:8391

Comment 7 errata-xmlrpc 2025-06-04 11:43:48 UTC
This issue has been addressed in the following products:

  Red Hat Enterprise Linux 8.4 Advanced Mission Critical Update Support

Via RHSA-2025:8507 https://access.redhat.com/errata/RHSA-2025:8507

Comment 8 errata-xmlrpc 2025-06-05 10:54:49 UTC
This issue has been addressed in the following products:

  Red Hat Enterprise Linux 8.6 Advanced Mission Critical Update Support
  Red Hat Enterprise Linux 8.6 Update Services for SAP Solutions
  Red Hat Enterprise Linux 8.6 Telecommunications Update Service

Via RHSA-2025:8594 https://access.redhat.com/errata/RHSA-2025:8594

Comment 9 errata-xmlrpc 2025-06-10 09:38:25 UTC
This issue has been addressed in the following products:

  Red Hat Enterprise Linux 8

Via RHSA-2025:8756 https://access.redhat.com/errata/RHSA-2025:8756

Comment 10 errata-xmlrpc 2025-06-10 15:05:10 UTC
This issue has been addressed in the following products:

  Red Hat Enterprise Linux 8.8 Update Services for SAP Solutions
  Red Hat Enterprise Linux 8.8 Telecommunications Update Service

Via RHSA-2025:8784 https://access.redhat.com/errata/RHSA-2025:8784