UBUNTU-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.

References

Affected packages

Ubuntu:22.04:LTS / thunderbird

Package

Name: thunderbird
Purl: pkg:deb/ubuntu/thunderbird@1:128.12.0+build1-0ubuntu0.22.04.1?arch=source&distro=jammy

Affected ranges

Type: ECOSYSTEM
Events: Introduced

0Unknown introduced version / All previous versions are affected

Fixed

1:128.12.0+build1-0ubuntu0.22.04.1

Affected versions

1:91.*

1:91.1.2+build1-0ubuntu1

1:91.3.0+build2-0ubuntu1

1:91.3.1+build1-0ubuntu1

1:91.3.2+build1-0ubuntu1

1:91.4.0+build1.1-0ubuntu1

1:91.4.0+build2-0ubuntu1

1:91.5.0+build1-0ubuntu1

1:91.5.1+build1-0ubuntu1

1:91.6.1+build1-0ubuntu1

1:91.7.0+build1-0ubuntu1

1:91.7.0+build2-0ubuntu1

1:91.8.0+build2-0ubuntu1

1:91.9.1+build1-0ubuntu0.22.04.1

1:91.11.0+build2-0ubuntu0.22.04.1

1:102.*

1:102.2.2+build1-0ubuntu0.22.04.1

1:102.4.2+build2-0ubuntu0.22.04.1

1:102.7.1+build2-0ubuntu0.22.04.1

1:102.8.0+build2-0ubuntu0.22.04.1

1:102.9.0+build1-0ubuntu0.22.04.1

1:102.10.0+build2-0ubuntu0.22.04.1

1:102.11.0+build1-0ubuntu0.22.04.1

1:102.13.0+build1-0ubuntu0.22.04.1

1:102.15.0+build1-0ubuntu0.22.04.1

1:102.15.1+build1-0ubuntu0.22.04.1

1:115.*

1:115.3.1+build1-0ubuntu0.22.04.2

1:115.4.1+build1-0ubuntu0.22.04.1

1:115.5.0+build1-0ubuntu0.22.04.1

1:115.6.0+build2-0ubuntu0.22.04.1

1:115.8.1+build1-0ubuntu0.22.04.1

1:115.9.0+build1-0ubuntu0.22.04.1

1:115.10.1+build1-0ubuntu0.22.04.1

1:115.11.0+build2-0ubuntu0.22.04.1

1:115.12.0+build3-0ubuntu0.22.04.1

1:115.13.0+build5-0ubuntu0.22.04.1

1:115.15.0+build1-0ubuntu0.22.04.1

1:115.16.0+build2-0ubuntu0.22.04.1

1:115.18.0+build1-0ubuntu0.22.04.1

Ecosystem specific

{
    "binaries": [
        {
            "binary_version": "1:128.12.0+build1-0ubuntu0.22.04.1",
            "binary_name": "thunderbird"
        },
        {
            "binary_version": "1:128.12.0+build1-0ubuntu0.22.04.1",
            "binary_name": "thunderbird-dev"
        },
        {
            "binary_version": "1:128.12.0+build1-0ubuntu0.22.04.1",
            "binary_name": "thunderbird-gnome-support"
        },
        {
            "binary_version": "1:128.12.0+build1-0ubuntu0.22.04.1",
            "binary_name": "thunderbird-mozsymbols"
        },
        {
            "binary_version": "1:128.12.0+build1-0ubuntu0.22.04.1",
            "binary_name": "xul-ext-calendar-timezones"
        },
        {
            "binary_version": "1:128.12.0+build1-0ubuntu0.22.04.1",
            "binary_name": "xul-ext-gdata-provider"
        },
        {
            "binary_version": "1:128.12.0+build1-0ubuntu0.22.04.1",
            "binary_name": "xul-ext-lightning"
        }
    ],
    "availability": "No subscription required"
}