AccessControl/AuthEncoding.py in Zope before 2.13.19, as used in Plone before 4.2.3 and 4.3 before beta 1, allows remote attackers to obtain passwords via vectors involving timing discrepancies in password validation.

A HTTP header injection flaw was found in the way Plone, a user friendly and powerful content management system, performed sanitization of HTTP headers provided within certain URL requests. A remote attacker could provide a specially-crafted URL that, when processed would lead the injected HTTP headers to be returned as part of Plone system HTTP response (possibly leading to HTTP response splitting, cross-site scripting [XSS] flaws, session fixation or unauthorized HTTP redirect attacks - to mention some of the possible negative consequences).

References: [1] http://plone.org/products/plone/security/advisories/20121106/02 [2] http://plone.org/products/plone/security/advisories/20121106/

Relevant upstream HotFixes: [3] http://plone.org/products/plone-hotfix/releases/20121106

From the OSS post: [4] http://www.openwall.com/lists/oss-security/2012/11/07/4

the setHeader.py change from upstream HotFix is relevant to this issue.