Heap-based buffer overflow in the nsTransformedTextRun function in Mozilla Firefox before 33.0, Firefox ESR 31.x before 31.2, and Thunderbird 31.x before 31.2 allows remote attackers to execute arbitrary code via Cascading Style Sheets (CSS) token sequences that trigger changes to capitalization style.
The product performs operations on a memory buffer, but it reads from or writes to a memory location outside the buffer's intended boundary. This may result in read or write operations on unexpected memory locations that could be linked to other variables, data structures, or internal program data.