CVE-2025-3035: Tab title disclosure across pages when using AI chatbot

Severity: medium (CVSS 5.3 v3.1)
Exploited in the wild: not listed in CISA KEV
EPSS: 0.3% probability of exploitation in the next 30 days
Public exploit or detection template: none known
Published: 2025-04-01 · updated 2026-09-30
Weakness: CWE-359

Description

By first using the AI chatbot in one tab and later activating it in another tab, the document title of the previous tab would leak into the chat prompt. This vulnerability was fixed in Firefox 137.

Affected products

Mozilla Firefox: before 137.0 — fixed in 137.0

How to fix

Upgrade to a fixed version: Mozilla Firefox 137.0. Check the vendor advisory for mitigations.

References

https://bugzilla.mozilla.org/show_bug.cgi?id=1952268
https://www.mozilla.org/security/advisories/mfsa2025-20/

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