What is CVE-2025-1015?

CVE-2025-1015 is a medium-severity vulnerability in Mozilla Thunderbird, classified under Cross-site Scripting. CVSS score: 5.4/10. Published 2025-02-04.

How severe is CVE-2025-1015?

Medium severity. CVSS v3 base score is 5.4 out of 10.

Is CVE-2025-1015 known to be exploited?

6 public proof-of-concept repositories are indexed. Not currently listed in the CISA KEV catalog.

XSS in Mozilla Thunderbird

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.

Vulnerability class: XSS (Cross-Site Scripting)

EPSS: 0.013 (68.2th percentile) — read the EPSS interpretation.

CVSS v3 metric

CVSS v3 base score 5.4 (Medium). Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:L/I:L/A:N.

Affected products

Mozilla Thunderbird — versions 128.7, 135

Weakness classification (CWE)

CWE-79 — Cross-site Scripting

Public proof-of-concept exploits

References

security@mozilla.org (Permissions Required)
security@mozilla.org (Vendor Advisory)
security@mozilla.org

Frequently asked questions

What is CVE-2025-1015?: CVE-2025-1015 is a medium-severity vulnerability in Mozilla Thunderbird, classified under Cross-site Scripting. CVSS score: 5.4/10. Published 2025-02-04.
How severe is CVE-2025-1015?: Medium severity. CVSS v3 base score is 5.4 out of 10.
Is CVE-2025-1015 known to be exploited?: 6 public proof-of-concept repositories are indexed. Not currently listed in the CISA KEV catalog.