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.
The product reads data past the end, or before the beginning, of the intended buffer.
| Link | Tags |
|---|---|
| http://www.securitytracker.com/id/1040273 | third party advisory vdb entry |
| https://usn.ubuntu.com/3554-1/ | third party advisory vendor advisory |
| https://www.debian.org/security/2018/dsa-4098 | third party advisory vendor advisory |
| https://curl.haxx.se/docs/adv_2018-824a.html | patch vendor advisory |
| https://github.com/curl/curl/pull/2231 | patch third party advisory issue tracking |
| https://access.redhat.com/errata/RHSA-2019:1543 | vendor advisory |