Fixed
Created: Oct 31, 2016
Updated: Dec 3, 2018
Resolved Date: Nov 8, 2016
Found In Version: 6.0
Fix Version: 6.0.0.32
Severity: Standard
Applicable for: Wind River Linux 6
Component/s: Userspace
Project cURL Security Advisory, November 2, 2016 -
[Permalink](https://curl.haxx.se/docs/adv_20161102C.html)
VULNERABILITY
-------------
In libcurl's base64 encode function, the output buffer is allocated as follows
without any checks on insize:
malloc( insize * 4 / 3 + 4 )
On systems with 32-bit addresses in userspace (e.g. x86, ARM, x32), the
multiplication in the expression wraps around if insize is at least 1GB of
data. If this happens, an undersized output buffer will be allocated, but the
full result will be written, thus causing the memory behind the output buffer
to be overwritten.
If a username is set directly via `CURLOPT_USERNAME` (or curl's `-u, --user`
option), this vulnerability can be triggered. The name has to be at least
512MB big in a 32bit system.
Systems with 64 bit versions of the `size_t` type are not affected by this
issue.
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 7.1 to and including 7.50.3
- Not affected versions: curl >= 7.51.0
libcurl is used by many applications, but not always advertised as such!
THE SOLUTION
------------
In version 7.51.0, these functions will deny negative string lengths from
being used.
A [patch for CVE-2016-XXXX](https://curl.haxx.se/s3c/C.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 use the `CURLOPT_USERNAME` option.
