Bug 787109 (CVE-2012-0877) - CVE-2012-0877 PyXML: hash table collisions CPU usage DoS (oCERT-2011-003)
Summary: CVE-2012-0877 PyXML: hash table collisions CPU usage DoS (oCERT-2011-003)
Alias: CVE-2012-0877
Product: Security Response
Classification: Other
Component: vulnerability
Version: unspecified
Hardware: All
OS: Linux
Target Milestone: ---
Assignee: Red Hat Product Security
QA Contact:
Depends On:
Blocks: hashdos, oCERT-2011-003 782164
TreeView+ depends on / blocked
Reported: 2012-02-03 07:28 UTC by Kurt Seifried
Modified: 2021-02-24 13:13 UTC (History)
7 users (show)

Fixed In Version:
Doc Type: Bug Fix
Doc Text:
Clone Of:
Last Closed: 2015-01-17 04:45:23 UTC

Attachments (Terms of Use)

Description Kurt Seifried 2012-02-03 07:28:57 UTC
However upstream PyXML will still be affected

Juraj Somorovsky reported that certain XML parsers/servers are affected by the
same, or similar, flaw as the hash table collisions CPU usage denial of
service.  Sending a specially crafted message to an XML service can result in
longer processing time, which could lead to a denial of service.  It is
reported that this attack on XML can be applied on different XML nodes (such as
entities, element attributes, namespaces, various elements in the XML security,

PyXML is written in Python and makes significant use of arrays. It is unclear if fixing the Python array hash DoS bug (Bz 750555) will completely address this issue however at first glance it would appear to be the case. In other words no action should be neccesary from upstream to correct this.

Additionally our PyXML uses the system expat (from the spec file):

# build PyXML with system expat
# Make sure we don't use local one

which is covered in bug: 787080

Comment 1 Kurt Seifried 2012-02-03 07:31:17 UTC
Packages that require PyXML:


Comment 6 Kurt Seifried 2015-01-17 04:45:23 UTC

This issue affects the versions of xerces as shipped with Red Hat Enterprise Linux 6. Red Hat Product Security has rated this issue as having Moderate security impact. A future update may address this issue. For additional information, refer to the Issue Severity Classification: https://access.redhat.com/security/updates/classification/.

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