Apache Tomcat 5.5.0 through 5.5.29, 6.0.0 through 6.0.27, and 7.0.0 beta does not properly handle an invalid Transfer-Encoding header, which allows remote attackers to cause a denial of service (application outage) or obtain sensitive information via a crafted header that interferes with "recycling of a buffer."
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.