IBM WebSphere Application Server - Liberty 20.0.0.12 through 26.0.0.10 could allow an unauthenticated remote attacker to bypass access controls configured on gRPC service methods.
IBM strongly recommends addressing the vulnerability now by applying a currently available interim fix or fix pack that contains the fix for APAR DT502929. 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 https://www.ibm.com/support/pages/node/6553910 .
For IBM WebSphere Application Server Liberty 20.0.0.12 - 26.0.0.10 using the grpc-1.0 feature:
· Upgrade to minimal fix pack levels as required by the interim fix and then apply the Interim Fix that resolves DT502929 https://www.ibm.com/support/pages/node/7277460
--OR--
· Apply Liberty Fix Pack 26.0.0.11 or later (targeted availability 4Q2026).
Additional interim fixes may be available and linked off the interim fix download page.