curl / Mailing Lists / curl-library / Single Mail
Buy commercial curl support from WolfSSL. We help you work out your issues, debug your libcurl applications, use the API, port to new platforms, add new features and more. With a team lead by the curl founder himself.

[SECURITY ADVISORY] curl: Integer overflows in curl_url_set

From: Daniel Stenberg via curl-library <curl-library_at_cool.haxx.se>
Date: Wed, 22 May 2019 09:23:51 +0200 (CEST)

Integer overflows in `curl_url_set()`
=====================================

Project curl Security Advisory, May 22nd 2019 -
[Permalink](https://curl.haxx.se/docs/CVE-2019-5435.html)

VULNERABILITY
-------------

libcurl contains two integer overflows in the `curl_url_set()` function that
if triggered, can lead to a too small buffer allocation and a subsequent heap
buffer overflow.

The flaws only exist on 32 bit architectures and require excessive string
input lengths.

We are not aware of any exploit of this flaw.

INFO

----
There are two entry points to this issue, on 32 bit architectures.
By asking libcurl to parse a string, passing in a string longer than 2GB to
this API: `curl_url_set(uh, CURLUPART_URL, "string", 0);` triggers the bug.
Asking libcurl to update a URL with a new string, and URL encoded it in the
process, by passing in a string longer than 1.33GB to this API:
`curl_url_set(uh, CURLUPART_*, "string", CURLU_URLENCODE);` triggers the bug.
This bug was introduced in August 2018 in
[commit fb30ac5a2d](https://github.com/curl/curl/commit/fb30ac5a2d63773c52).
The Common Vulnerabilities and Exposures (CVE) project has assigned the name
CVE-2019-5435 to this issue.
CWE-131: Incorrect Calculation of Buffer Size
Severity: 3.7 (Low)
AFFECTED VERSIONS
-----------------
- Affected versions: libcurl 7.62.0 to and including 7.64.1
- Not affected versions: libcurl < 7.62.0 and >= libcurl 7.65.0
libcurl is used by many applications, but not always advertised as such.
THE SOLUTION
------------
A [fix for CVE-2019-5435](https://github.com/curl/curl/commit/5fc28510a4664f4) is already merged.
RECOMMENDATIONS
--------------
We suggest you take one of the following actions immediately, in order of
preference:
  A - Upgrade curl to version 7.65.0
  B - Apply the patch to your version and rebuild
TIMELINE
--------
The issue was reported to the curl project on April 24, 2019. The patch was
communicated to the reporter on April 25, 2019. We contacted distros_at_openwall
on May 15.
curl 7.65.0 was released on May 22 2019, coordinated with the publication of
this advisory.
CREDITS
-------
Reported by Wenchao Li. Patch by Daniel Stenberg
Thanks a lot!
-- 
  / daniel.haxx.se | Get the best commercial curl support there is - from me
                   | Private help, bug fixes, support, ports, new features
                   | https://www.wolfssl.com/contact/
-------------------------------------------------------------------
Unsubscribe: https://cool.haxx.se/list/listinfo/curl-library
Etiquette:   https://curl.haxx.se/mail/etiquette.html
Received on 2019-05-22