invalid URL parsing with '#'
Project curl Security Advisory, November 2, 2016 - Permalink
curl doesn't parse the authority component of the URL correctly when the host name part ends with a '#' character, and could instead be tricked into connecting to a different host. This may have security implications if you for example use a URL parser that follows the RFC to check for allowed domains before using curl to request them.
http://firstname.lastname@example.org/x.txt would wrongly make curl send a request to evil.com while your browser would connect to example.com given the same URL.
The problem exists for most protocol schemes.
We are not aware of any exploit of this flaw.
The Common Vulnerabilities and Exposures (CVE) project has assigned the name CVE-2016-8624 to this issue.
CWE-172: Encoding Error
This flaw exists in the following curl versions.
- Affected versions: curl 6.0 to and including 7.50.3
- Not affected versions: curl < 6.0 and curl >= 7.51.0
libcurl is used by many applications, but not always advertised as such!
In version 7.51.0, the parser function is fixed.
A patch for CVE-2016-8624 is available.
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 - Strip out the parts of the URLs containing '#' before passing them to curl
It was first reported to the curl project on October 10 by Fernando Muñoz.
We contacted distros@openwall on October 19.
curl 7.51.0 was released on November 2 2016, coordinated with the publication of this advisory.
- Reported-by: Fernando Muñoz
- Patched-by: Daniel Stenberg
Thanks a lot!