IJ57653: PQC HYBRID KEY EXCHANGE IS NOT THREAD SAFE

APAR status

• Closed as program error.

Error description

• Error Message: error: java.lang.RuntimeException: Could not
  generate MLKEM Secret Key : ...Caused by:
  java.security.InvalidKeyException: An incorrect key was
  specified. Key must be either a PQCPublicKey or a
  PQCKEMSecret.with X25519MLKEM768 is enabled.
  .
  Stack Trace: <OSB>2/5/26 8:32:24:060 CET<CSB> 00000343 SystemOut
      O   javax.net.ssl<PIPE>WARNING<PIPE>03
  43<PIPE>pool-8-thread-27<PIPE>2026-02-05 08:32:24.060
  CET<PIPE>Thread.java:1175<PIPE>handling exception (
  "throwable" : {
    java.lang.RuntimeException: Could not generate MLKEM Secret
  Key
  at com.ibm.jsse2.P$d.d(P$d.java:26)
  at com.ibm.jsse2.ap$d.a(ap$d.java:41)
  at com.ibm.jsse2.o.a(o.java:137)
  ...
    Caused by: java.security.InvalidKeyException: An incorrect key
  was specified. Key must be either a PQCPublicKey or a
  PQCKEMSecret.
  at
  com.ibm.crypto.plus.provider.PQCKEMKeyAgreementImpl.engineDoPhas
  e(PQCKEMKeyAgreementImpl.java:78)
  at javax.crypto.KeyAgreement.doPhase(KeyAgreement.java:93)
  at com.ibm.jsse2.P$d.d(P$d.java:57)
  ... 32 more}
  .
  Disabling  X25519MLKEM768 the problem goes away
  

Local fix

• Disable the PQC Hybrid Key Exchange algorithms
  

Problem summary

• PQC Hybrid Key Exchange algorithms are  not thread safe
  

Problem conclusion

• Binary affected - ibmjsseprovider2.jar
  GIT Issue - 400
  RTC - 153870
  Build - 8.0 build_20260309--612
  JVM to be delivered in - JDK 8 SR8FP65
  .
  This APAR will be fixed in the following Releases:
  .
  IBM Semeru Runtimes
  IBM SDK, Java Technology Edition
     8    SR8 FP65  (8.0.8.65)
  .
  Downloads and supplementary documentation can be found at the
  following locations:
  - For non z/OS operating systems:
    - IBM Semeru Runtimes, Version 11 and later
      https://www.ibm.com/semeru-runtimes/downloads/
    - IBM SDK, Java Technology Edition, Version 8
      https://www.ibm.com/support/pages/java-sdk-downloads/
  - For the z/OS operating system:
    - Java SDK Products on z/OS
      https://www.ibm.com/support/pages/java-sdk-products-zos
  

Temporary fix

Comments

APAR Information

• APAR is sysrouted FROM one or more of the following:

• APAR is sysrouted TO one or more of the following:

Fix information

• Fixed component name

  SECURITY

• Fixed component ID

  620700125

Applicable component levels