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VulnerabilityPublished Updated

CVE-2025-1015: Mozilla Thunderbird · Cross-site Scripting

Affects Mozilla ThunderbirdSource CVE Database V5

0

Not known to be exploited · CVSS 5.4 Medium : upgrade to 128.7 when convenient.

Data as of 26 Oct 2026, 12:55 UTC

CVSS 3.1 base score
5.4Medium
How severe the flaw is on the 0–10 CVSS scale.
EPSS
1.3% chance of exploitation in 30 days – higher than 71% of CVEsExploit Prediction Scoring System: the likelihood attackers will use this flaw soon.
Patch
Available – fixed in 128.7
CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:L/I:L/A:N

Exploitation evidence

  1. Disclosed: evidence found.

    CVE published 4 Feb 2025

  2. Detectable: no evidence on record.

    No public nuclei template indexed

  3. Weaponised: no evidence on record.

    No public exploit code indexed in Metasploit or Exploit-DB

  4. Exploited in the wild: no evidence on record.

    Not in CISA KEV and no source reports exploitation

  5. Observed by OffSeq Mirage: no evidence on record.

    No attack traffic recorded by OffSeq Mirage sensors

A missing step is not evidence of safety. Sources: cve.org (opens in a new tab), the Metasploit, Exploit-DB and nuclei-templates index as of 26 Oct 2026.

What to do

Upgrade Mozilla Thunderbird to 128.7.

Affected software

ProductAffectedFixed in
Mozilla ThunderbirdAffected
  • <128.7
Fixed in
  • 128.7

AI-suggested

This vulnerability has been fixed in Thunderbird versions 128.7 and 135. Users and administrators should update to at least Thunderbird 128.7 or later to remediate this issue. Since official fixes are available, applying these updates is the recommended mitigation. No additional action is required once the update is applied.

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.

References

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