Exposure of Sensitive Information to an Unauthorized Actor Affecting Firefox package, versions [,155)
Threat Intelligence
The probability is the direct output of the EPSS model, and conveys an overall sense of the threat of exploitation in the wild. The percentile measures the EPSS probability relative to all known EPSS scores. Note: This data is updated daily, relying on the latest available EPSS model version. Check out the EPSS documentation for more details.
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- published11 Oct 2026
- disclosed11 Oct 2026
- creditUnknown
Introduced: 11 Oct 2026
NewCVE-2026-84140 (opens in a new tab)How to fix?
Upgrade Firefox to version 155 or higher.
Overview
Affected versions of this package are vulnerable to Exposure of Sensitive Information to an Unauthorized Actor due to improper enforcement of site isolation in the Navigation component. An attacker can access or manipulate data from other sites by exploiting cross-origin navigation processes.