IBM WebSphere Application Server - Liberty 19.0.0.7 through 26.0.0.5 and IBM WebSphere Application Server 9.0, and 8.5 and WebSphere Application Server Liberty are vulnerable to a denial of service, caused by sending a specially-crafted request. A remote attacker could exploit this vulnerability to cause the server to consume memory resources.
IBM strongly recommends addressing the vulnerability now by applying a currently available interim fix or fix pack that contains the fix for APAR PH70807 and APAR PH70616. To determine if a feature is enabled for WebSphere Application Server Liberty, refer to How to determine if Liberty is using a specific feature https://www.ibm.com/support/pages/node/6553910 .
For IBM WebSphere Application Server Liberty 19.0.0.7 - 26.0.0.5 using the sipServlet-1.1 feature:
· Upgrade to minimal fix pack levels as required by the interim fix and then apply the Interim Fix that resolves PH70807 https://www.ibm.com/support/pages/node/7273237
--OR--
· Apply Fix Pack 26.0.0.6 or later (targeted availability 2Q2026).
For IBM WebSphere Application Server traditional:
For V9.0.0.0 through 9.0.5.27:
· Upgrade to minimal fix pack levels as required by the interim fix and then apply the Interim Fix that resolves PH70616 https://www.ibm.com/support/pages/node/7269402
--OR--
· Apply Fix Pack 9.0.5.28 or later (targeted availability 2Q2026).
For V8.5.0.0 through 8.5.5.29:
· Upgrade to minimal fix pack levels as required by interim fix and then apply Interim Fix that resolves PH70616 https://www.ibm.com/support/pages/node/7269402
--OR--
· Apply Fix Pack 8.5.5.30 or later (targeted availability 3Q2026).
Additional interim fixes may be available and linked off the interim fix download page.