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CVE-2026-109757

High

Description

Sandbox escape due to race condition in the Networking component. This vulnerability was fixed in Firefox 158, Firefox ESR 153.5, Thunderbird 158, and Thunderbird 153.5.

SeverityHigh
CVSS8.3
Exploit probability—
ProductFirefox
PublishedOct 13, 2026
First seenOct 13, 2026
Weakness typeCWE-362Race condition

How to fix

Update
  • Firefox158 or later
  • Firefox ESR153.5 or later
  • Thunderbird158, 153.5 or later

Affected products

ProductAffected versionsFixed in
FirefoxNo range specified158
Firefox ESRNo range specified153.5
ThunderbirdNo range specified158, 153.5

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