CVE-2018-1000005

libcurl 7.49.0 to and including 7.57.0 contains an out bounds read in code
handling HTTP/2 trailers. It was reported
(https://github.com/curl/curl/pull/2231) that reading an HTTP/2 trailer
could mess up future trailers since the stored size was one byte less than
required. The problem is that the code that creates HTTP/1-like headers
from the HTTP/2 trailer data once appended a string like : to the target
buffer, while this was recently changed to : (a space was added after
the colon) but the following math wasn’t updated correspondingly. When
accessed, the data is read out of bounds and causes either a crash or that
the (too large) data gets passed to client write. This could lead to a
denial-of-service situation or an information disclosure if someone has a
service that echoes back or uses the trailers for something.