Follow @Openwall on Twitter for new release announcements and other news
[<prev] [next>] [day] [month] [year] [list]
Date: Wed, 31 Oct 2018 07:55:42 +0100 (CET)
From: Daniel Stenberg <>
To: curl security announcements -- curl users <>,,
        libcurl hacking <>,
Subject: [SECURITY ADVISORY] curl - use-after-free in handle close

use-after-free in handle close

Project curl Security Advisory, October 31st 2018 -


libcurl contains a heap use-after-free flaw in code related to closing an easy

When closing and cleaning up an "easy" handle in the `Curl_close()` function,
the library code first frees a struct (without nulling the pointer) and might
then subsequently erroneously write to a struct field within that already
freed struct.

We are not aware of any exploit of this flaw.


This bug was introduced in [commit
b46cfbc068](, February 2018.

The Common Vulnerabilities and Exposures (CVE) project has assigned the name
CVE-2018-16840 to this issue.

CWE-416: Use After Free

Severity: 2.3 (Low)


- Affected versions: libcurl 7.59.0 to and including 7.61.1
- Not affected versions: libcurl < 7.59.0 and >= 7.62.0

curl is used by many applications, but not always advertised as such.


A [patch for
is available.


We suggest you take one of the following actions immediately, in order of

  A - Upgrade curl to version 7.62.0

  B - Apply the patch to your version and rebuild


It was reported to the curl project on October 14, 2018.  We contacted
distros@...nwall on October 22.

curl 7.62.0 was released on October 31 2018, coordinated with the publication
of this advisory.


Reported by Brian Carpenter, Geeknik Labs. Patch by Daniel Stenberg.

Thanks a lot!



Powered by blists - more mailing lists

Please check out the Open Source Software Security Wiki, which is counterpart to this mailing list.

Confused about mailing lists and their use? Read about mailing lists on Wikipedia and check out these guidelines on proper formatting of your messages.