Security Bulletin: IBM WebSphere Application Server Liberty for IBM i is vulnerable to denial of service due to a flaw in handling multiplexed streams (CVE-2023-44487)

Summary

IBM WebSphere Application Server Liberty for IBM i is vulnerable to denial of service due to a flaw in handling multiplexed streams as described in the vulnerability details section. IBM i has addressed the vulnerability in IBM WebSphere Application Server Liberty with a fix as described in the remediation/fixes section.

Vulnerability Details

CVEID:CVE-2023-44487
**DESCRIPTION:**Multiple vendors are vulnerable to a denial of service, caused by a flaw in handling multiplexed streams in the HTTP/2 protocol. By sending numerous HTTP/2 requests and RST_STREAM frames over multiple streams, a remote attacker could exploit this vulnerability to cause a denial of service due to server resource consumption.
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

Remediation/Fixes

The issue can be fixed by applying a PTF to IBM i. IBM i releases 7.5, 7.4, 7.3, and 7.2 will be fixed.

The IBM i PTF numbers for 5770-SS1 Option 3 contain the fix for the vulnerability.

IBM i Release| 5770-SS1 Option 3
PTF Numbers| PTF Download Link
—|—|—
7.5| SI85401| <https://www.ibm.com/support/pages/ptf/SI85401&gt;
7.4| SI85402| <https://www.ibm.com/support/pages/ptf/SI85402&gt;
7.3| SI85403| <https://www.ibm.com/support/pages/ptf/SI85403&gt;
7.2| SI85404| <https://www.ibm.com/support/pages/ptf/SI85404&gt;

<https://www.ibm.com/support/fixcentral&gt;

Important note: IBM recommends that all users running unsupported versions of affected products upgrade to supported and fixed version of affected products.

Workarounds and Mitigations

None.