CVE-2025-1015: thunderbird XSS — Fix

Description

The Thunderbird Address Book URI fields contained unsanitized links. This could be used by an attacker to create and export an address book containing a malicious payload in a field. For example, in the “Other” field of the Instant Messaging section. If another user imported the address book, clicking on the link could result in opening a web page inside Thunderbird, and that page could execute (unprivileged) JavaScript. This vulnerability was fixed in Thunderbird 128.7 and Thunderbird 135.

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CVSS v3.1 Score

5.4

MEDIUM

CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:L/I:L/A:N

Weakness Type (CWE)

CWE-79 Cross-site Scripting (XSS)

Affected Products

Vendor	Product	Versions
mozilla	thunderbird	128.0.1 — 128.7.0

References

Advisories & Patches

https://www.mozilla.org/security/advisories/mfsa2025-10/

Other References

https://bugzilla.mozilla.org/show_bug.cgi?id=1939458 https://www.mozilla.org/security/advisories/mfsa2025-11/

Frequently Asked Questions

What is CVE-2025-1015? +

The Thunderbird Address Book URI fields contained unsanitized links. This could be used by an attacker to create and export an address book containing a malicious payload in a field. For example, in the “Other” field of the Instant Messaging section. If another user imported the address book, clicking on the link could result in opening a web page inside Thunderbird, and that page could execute (unprivileged) JavaScript. This vulnerability was fixed in Thunderbird 128.7 and Thunderbird 135. It has a CVSS v3.1 base score of 5.4 (MEDIUM).

How severe is CVE-2025-1015? +

CVE-2025-1015 has a CVSS v3.1 score of 5.4 out of 10, rated MEDIUM. This is a medium-severity vulnerability that should be remediated as part of regular maintenance.

What products are affected by CVE-2025-1015? +

CVE-2025-1015 affects products from mozilla, specifically: thunderbird. Check the affected products table above for specific version ranges.

How do I check if I'm vulnerable to CVE-2025-1015? +

You can use Secably's free Website Scanner to check your website for known vulnerabilities. For infrastructure scanning, use the Port Scanner to identify exposed services that may be affected. Check the vendor advisories linked above for specific patch and version information.

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