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case insensitive password comparison

Project curl Security Advisory, November 2, 2016 - Permalink


When re-using a connection, curl was doing case insensitive comparisons of username and password with the existing connections.

This means that if an unused connection with proper credentials exists for a protocol that has connection-scoped credentials, an attacker can cause that connection to be reused if s/he knows the case-insensitive version of the correct password.


The Common Vulnerabilities and Exposures (CVE) project has assigned the name CVE-2016-8616 to this issue.

CWE-178: Improper Handling of Case Sensitivity

Severity: Medium


This flaw exists in the following curl versions.

libcurl is used by many applications, but not always advertised as such!


In version 7.51.0, the comparisons are done case sensitively.


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 September 23 by Cure53.

We contacted distros@openwall on October 19.

curl 7.51.0 was released on November 2 2016, coordinated with the publication of this advisory.


This vulnerability was found during a Secure Open Source audit performed by Cure53.