Bug 1265781 (CVE-2015-4520)

Summary: CVE-2015-4520 Mozilla: Errors in the handling of CORS preflight request headers (MFSA 2015-111)
Product: [Other] Security Response Reporter: Prasad Pandit <ppandit>
Component: vulnerabilityAssignee: Red Hat Product Security <security-response-team>
Status: CLOSED ERRATA QA Contact:
Severity: high Docs Contact:
Priority: high    
Version: unspecifiedCC: cschalle, gecko-bugs-nobody, jhorak, stransky
Target Milestone: ---Keywords: Security
Target Release: ---   
Hardware: All   
OS: Linux   
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Fixed In Version: Doc Type: Bug Fix
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Last Closed: 2015-10-01 14:04:25 UTC Type: ---
Regression: --- Mount Type: ---
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oVirt Team: --- RHEL 7.3 requirements from Atomic Host:
Cloudforms Team: --- Target Upstream Version:
Embargoed:
Bug Depends On:    
Bug Blocks: 1261782    

Description Prasad Pandit 2015-09-23 18:01:32 UTC 
Mozilla developer Ehsan Akhgari reported two issues with Cross-origin resource
sharing (CORS) "preflight" requests.

The first issue is that in some circumstances the same cache key can be
generated for two preflight requests on a site. As a result, if a second
request is made that will match the cached key generated by an earlier
request, CORS checks will be bypassed because the system will see the
previously cached request as applicable.

In the second issue, when some Access-Control- headers are missing from CORS
responses, the values from different Access-Control- headers can be used that
present in the same response.

External Reference:

https://www.mozilla.org/en-US/security/advisories/mfsa2015-111/
Comment 1 Martin Prpič 2015-09-24 12:38:20 UTC 
Acknowledgements:

Red Hat would like to thank the Mozilla project for reporting this issue. Upstream acknowledges Ehsan Akhgari as the original reporter.
Comment 2 errata-xmlrpc 2015-09-24 18:40:40 UTC 
This issue has been addressed in the following products:

  Red Hat Enterprise Linux 5
  Red Hat Enterprise Linux 7
  Red Hat Enterprise Linux 6

Via RHSA-2015:1834 https://rhn.redhat.com/errata/RHSA-2015-1834.html
Comment 4 errata-xmlrpc 2015-10-01 13:26:33 UTC 
This issue has been addressed in the following products:

  Red Hat Enterprise Linux 5
  Red Hat Enterprise Linux 7
  Red Hat Enterprise Linux 6

Via RHSA-2015:1852 https://rhn.redhat.com/errata/RHSA-2015-1852.html