CVE-2023-5171: Debian Linux

Medium severity, CVSS 6.5. EPSS: 1.1% chance of exploitation in the next 30 days.

During Ion compilation, a Garbage Collection could have resulted in a use-after-free condition, allowing an attacker to write two NUL bytes, and cause a potentially exploitable crash. This vulnerability affects Firefox < 118, Firefox ESR < 115.3, and Thunderbird < 115.3.

Affected products

• Debian Debian Linux: version 10.0 only; version 11.0 only; version 12.0 only
• Fedoraproject Fedora: version 39 only
• Mozilla Firefox: before 118 (fixed in 118)
• Mozilla Firefox ESR: before 115.3 (fixed in 115.3)
• Mozilla Thunderbird: before 115.3 (fixed in 115.3)

Published 2023-09-27. Last modified 2026-06-17.