CVE-2023-23602: Mozilla Firefox

Medium severity, CVSS 6.5. EPSS: 0.6% chance of exploitation in the next 30 days.

A mishandled security check when creating a WebSocket in a WebWorker caused the Content Security Policy connect-src header to be ignored. This could lead to connections to restricted origins from inside WebWorkers. This vulnerability affects Firefox < 109, Firefox ESR < 102.7, and Thunderbird < 102.7.

Affected products

• Mozilla Firefox: before 109.0 (fixed in 109.0)
• Mozilla Firefox ESR: before 102.7 (fixed in 102.7)
• Mozilla Thunderbird: before 102.7 (fixed in 102.7)

Published 2023-06-02. Last modified 2026-06-17.