Out-of-bounds Read

Affecting curl package, versions <7.52.1-5+deb9u4

Overview

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.

References

• CONFIRM
• CVE Details
• Debian Security Advisory
• Debian Security Tracker
• GitHub PR
• RHSA Security Advisory
• Security Tracker
• Ubuntu CVE Tracker
• Ubuntu Security Advisory