curl_getdate read out of bounds
Project curl Security Advisory, November 2, 2016 - Permalink
curl_getdate converts a given date string into a numerical timestamp and
it supports a range of different formats and possibilites to express a date
and time. The underlying date parsing function is also used internally when
parsing for example HTTP cookies (possibly received from remote servers) and
it can be used when doing conditional HTTP requests.
The date parser function uses the libc sscanf() function at two places, with the parsing strings "%02d:%02d" and ""%02d:%02d:%02d". The intent being that it would parse either a string with HH:MM (two digits colon two digits) or HH:MM:SS (two digits colon two digits colon two digits). If instead the piece of time that was sent in had the final digit cut off, thus ending with a single-digit, the date parser code would advance its read pointer one byte too much and end up reading out of bounds.
We are not aware of any exploit of this flaw.
The Common Vulnerabilities and Exposures (CVE) project has assigned the name CVE-2016-8621 to this issue.
This flaw exists in the following curl versions.
- Affected versions: curl 7.12.2 to and including 7.50.3
- Not affected versions: curl < 7.12.2 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-2016-8621 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
It was first reported to the curl project on October 3 by Luật Nguyễn.
We contacted distros@openwall on October 19.
curl 7.51.0 was released on November 2 2016, coordinated with the publication of this advisory.
Thanks to Luật Nguyễn.