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Security Bulletin: Multiple Vulnerabilities in Expat component shipped with IBM Rational ClearCase ( CVE-2021-45960, CVE-2021-46143 )

Security Bulletin


libexpat is a stream-oriented XML parser library used by IBM Rational ClearCase. IBM Rational ClearCase has addressed the applicable CVEs.

Vulnerability Details

CVEID:   CVE-2021-46143
DESCRIPTION:   Expat could allow a remote attacker to execute arbitrary code on the system, caused by an integer overflow of m_groupSize in doProlog in xmlparse.c. By persuading a victim to open a specially-crafted file, an attacker could exploit this vulnerability to execute arbitrary code on the system.
CVSS Base score: 7.8
CVSS Temporal Score: See: for the current score.
CVSS Vector: (CVSS:3.0/AV:L/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H)

CVEID:   CVE-2021-45960
DESCRIPTION:   Expat (aka libexpat) is vulnerable to a denial of service, caused by a realloc misbehavior issue in the storeAtts function in xmlparse.c. By persuading a victim to open a specially-crafted XML content, a remote attacker could exploit this vulnerability to cause a the application to crash.
CVSS Base score: 5.5
CVSS Temporal Score: See: for the current score.
CVSS Vector: (CVSS:3.0/AV:L/AC:L/PR:N/UI:R/S:U/C:N/I:N/A:H)

Affected Products and Versions

Affected Product(s)Version(s)
IBM Rational ClearCase8.0.0
IBM Rational ClearCase9.0
IBM Rational ClearCase9.0.1
IBM Rational ClearCase9.1
IBM Rational ClearCase9.0.2
IBM Rational ClearCase8.0.1


Apply a fix pack as listed in the table below. The fix pack includes Expat 2.4.6.

Affected Versions
Applying the fix
9.1 through Rational ClearCase Fix Pack 3 ( for 9.1
9.0.2 through Rational ClearCase Fix Pack 6 ( for 9.0.2
9.0.1 through
9.0 through
Install Rational ClearCase Fix Pack 14 ( for 9.0.1

For 8.0.X and earlier releases, IBM recommends upgrading to a fixed, supported version/release/platform of the product.

Workarounds and Mitigations


Get Notified about Future Security Bulletins



Change History

25 Jul 2022: Initial Publication

*The CVSS Environment Score is customer environment specific and will ultimately impact the Overall CVSS Score. Customers can evaluate the impact of this vulnerability in their environments by accessing the links in the Reference section of this Security Bulletin.


According to the Forum of Incident Response and Security Teams (FIRST), the Common Vulnerability Scoring System (CVSS) is an "industry open standard designed to convey vulnerability severity and help to determine urgency and priority of response." IBM PROVIDES THE CVSS SCORES ""AS IS"" WITHOUT WARRANTY OF ANY KIND, INCLUDING THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE. CUSTOMERS ARE RESPONSIBLE FOR ASSESSING THE IMPACT OF ANY ACTUAL OR POTENTIAL SECURITY VULNERABILITY. In addition to other efforts to address potential vulnerabilities, IBM periodically updates the record of components contained in our product offerings. As part of that effort, if IBM identifies previously unidentified packages in a product/service inventory, we address relevant vulnerabilities regardless of CVE date. Inclusion of an older CVEID does not demonstrate that the referenced product has been used by IBM since that date, nor that IBM was aware of a vulnerability as of that date. We are making clients aware of relevant vulnerabilities as we become aware of them. "Affected Products and Versions" referenced in IBM Security Bulletins are intended to be only products and versions that are supported by IBM and have not passed their end-of-support or warranty date. Thus, failure to reference unsupported or extended-support products and versions in this Security Bulletin does not constitute a determination by IBM that they are unaffected by the vulnerability. Reference to one or more unsupported versions in this Security Bulletin shall not create an obligation for IBM to provide fixes for any unsupported or extended-support products or versions.

Document Location


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Document Information

Modified date:
25 July 2022