Fixed
Created: Oct 31, 2016
Updated: Oct 9, 2018
Resolved Date: Nov 8, 2016
Found In Version: 7.0
Fix Version: 7.0.0.22
Severity: Standard
Applicable for: Wind River Linux 7
Component/s: Userspace
VULNERABILITY
-------------
libcurl explicitly allows users to share cookies between multiple easy handles
that are concurrently employed by different threads.
When cookies to be sent to a server are collected, the matching function
collects all cookies to send and the cookie lock is released immediately
afterwards. That funcion however only returns a list with *references* back to
the original strings for name, value, path and so on. Therefore, if another
thread quickly takes the lock and frees one of the original cookie structs
together with its strings, a use-after-free can occur and lead to information
disclosure. Another thread can also replace the contents of the cookies from
separate HTTP responses or API calls.
We are not aware of any exploit of this flaw.
INFO
----
The Common Vulnerabilities and Exposures (CVE) project has assigned the name
CVE-2016-XXXX to this issue.
AFFECTED VERSIONS
-----------------
This flaw exists in the following curl versions:
- Affected versions: curl 7.10.7 to and including 7.50.3
- Not affected versions: curl < 7.10.7 and curl >= 7.51.0
libcurl is used by many applications, but not always advertised as such!
THE SOLUTION
------------
In version 7.51.0, the function returning the cookies make deep copies.
A [patch for CVE-2016-XXXX](https://curl.haxx.se/s3c/I.patch) is available.
RECOMMENDATIONS
---------------
We suggest you take one of the following actions immediately, in order of
preference:
A - Upgrade curl and libcurl to version 7.51.0
B - Apply the patch to your version and rebuild
C - Do not share cookies between threads
