Project curl Security Advisory, November 2, 2016 - Permalink
curl does not parse the authority component of the URL correctly when the host
name part ends with a hash (#) 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.
Passing in http://example.com#@evil.com/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.
The Common Vulnerabilities and Exposures (CVE) project has assigned the name CVE-2016-8624 to this issue.
CWE-172: Encoding Error
Severity: Medium
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
- Introduced-in: https://github.com/curl/curl/commit/ae1912cb0d494b48d5
libcurl is used by many applications, but not always advertised as such!
In version 7.51.0, the parser function is fixed.
As a side-effect of this fix, using the # character as part of the user or
password fields in the URL is no longer supported. According to RFC 3986
section 2.3 it is
not allowed. See issue #1216
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.
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!