Versions: 7.49.0, 7.49.1, 7.50.0, 7.50.1, 7.50.2, 7.50.3, 7.51.0, 7.52.0, 7.52.1, 7.53.0, 7.53.1, 7.54.0, 7.54.1, 7.55.0, 7.55.1, 7.56.0, 7.56.1,
Versions: 8.0, 9.0,
Description Language: en
Description: 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.