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CVE-2026-117899

High

Description

Use-after-free in the Networking: HTTP component. This vulnerability was fixed in Firefox 159, Firefox ESR 115.44, Firefox ESR 153.6, Thunderbird 159, and Thunderbird 153.6.

SeverityHigh
CVSS8.8
Exploit probability—
ProductFirefox
PublishedOct 27, 2026
First seenOct 27, 2026
Weakness typeCWE-416Use after free

How to fix

Update
  • Firefox159 or later
  • Firefox ESR153.6 or later
  • Thunderbird153.6 or later

Affected products

ProductAffected versionsFixed in
FirefoxNo range specified159
Firefox ESRNo range specified153.6
ThunderbirdNo range specified153.6

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