Use-after-free in HTML5 string parser

Use-after-free in HTML5 string parser

Announced

March 8, 2016

Reporter

ca0nguyen

Impact

Critical

Products

Firefox, Firefox ESR, Thunderbird

Fixed in

• Firefox 45
• Firefox ESR 38.7
• Thunderbird 38.7
• Thunderbird 45

Description

Security researcher ca0nguyen, working with HP's Zero Day Initiative, reported a use-after-free issue in the HTML5 string parser when parsing a particular set of table-related tags in a foreign fragment context such as SVG. This results in a potentially exploitable crash.

In general this flaw cannot be exploited through email in the Thunderbird product because scripting is disabled, but is potentially a risk in browser or browser-like contexts.

References

• ZDI-CAN-3545: Mozilla Firefox nsHtml5TreeBuilder Array Indexing Remote Code Execution Vulnerability (CVE-2016-1960)