An IMAP FETCH response line indicates the size of the returned data, in number of bytes. When that response says the data is zero bytes, libcurl would pass on that (non-existing) data with a pointer and the size (zero) to the deliver-data function. libcurl's deliver-data function treats zero as a magic number and invokes strlen() on the data to figure out the length. The strlen() is called on a heap based buffer that might not be zero terminated so libcurl might read beyond the end of it into whatever memory lies after (or just crash) and then deliver that to the application as if it was actually downloaded.
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.
| Link | Tags |
|---|---|
| https://curl.haxx.se/docs/adv_20171023.html | vendor advisory |
| https://access.redhat.com/errata/RHSA-2017:3263 | vendor advisory |
| https://security.gentoo.org/glsa/201712-04 | vendor advisory |
| http://www.securitytracker.com/id/1039644 | third party advisory vdb entry |
| https://access.redhat.com/errata/RHSA-2018:3558 | vendor advisory |
| http://www.securityfocus.com/bid/101519 | third party advisory vdb entry |
| http://www.debian.org/security/2017/dsa-4007 | third party advisory vendor advisory |
| https://access.redhat.com/errata/RHSA-2018:2486 | vendor advisory |