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AUSCERT External Security Bulletin Redistribution
IBM WebSphere Application Server Liberty is vulnerable to a
denial of service (CVE-2023-44487)
16 November 2023
AusCERT Security Bulletin Summary
Product: WebSphere Application Server
Operating System: AIX
CVE Names: CVE-2023-44487
Comment: CVSS (Max): 7.5 CVE-2023-44487 (CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H)
CVSS Source: NIST
The following are listed in the CISA Known Exploited Vulnerabilities (KEV) Catalog:
CISA KEV CVE(s): CVE-2023-44487
CISA KEV URL: https://www.cisa.gov/known-exploited-vulnerabilities-catalog
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Security Bulletin: IBM WebSphere Application Server Liberty is vulnerable to a
denial of service (CVE-2023-44487)
Document number : 7076252
Modified date : 15 November 2023
Product : WebSphere Application Server
Component : Liberty
Software version : Liberty
Operating system(s): AIX
IBM WebSphere Application Server Liberty is vulnerable to a denial of service
with the servlet-3.1, servlet-4.0, servlet-5.0, or servlet-6.0 feature with the
HTTP/2 protocol enabled.
DESCRIPTION: Multiple vendors are vulnerable to a denial of service, caused by
a Rapid Reset flaw in the HTTP/2 protocol. By sending numerous HTTP/2 requests
and RST_STREAM frames over multiple streams, a remote attacker could consume
excessive server side resources.
CVSS Base score: 7.5
CVSS Temporal Score: See: https://exchange.xforce.ibmcloud.com/vulnerabilities/
268044 for the current score.
CVSS Vector: (CVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H)
Affected Products and Versions
|Affected Product(s) |Version(s) |
|IBM WebSphere Application Server Liberty|126.96.36.199-188.8.131.52|
IBM strongly recommends addressing the vulnerability now by applying a
currently available interim fix or fix pack that contains the APAR PH57878 . To
determine if a feature is enabled for IBM WebSphere Application Server Liberty,
refer to How to determine if Liberty is using a specific feature . To determine
if the HTTP/2 protocol is enabled with Liberty Servlet features see HTTP/2
Support for Liberty.
For IBM WebSphere Application Server Liberty 184.108.40.206 - 220.127.116.11 using the
servlet-3.1, servlet-4.0, servlet-5.0, or servlet-6.0 feature(s) with the HTTP/
2 protocol enabled:
. Upgrade to minimal fix pack levels as required by interim fix and then apply
Interim Fix PH57878
. Apply Liberty Fix Pack 18.104.22.168 or later (targeted availability 4Q2023).
Additional interim fixes may be available and linked off the interim fix
Workarounds and Mitigations
To determine if a feature is enabled for IBM WebSphere Application Server
Liberty, refer to How to determine if Liberty is using a specific feature .
15 Nov 2023: 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.
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