When IPv6 is enabled, the JDK uses dual stack IPv4/IPv6 sockets by default. Binding, connecting, or sending datagrams uses IPv4-mapped IPv6 addresses in this case.

On some hosts running macOS version 15.6.x and above, and macOS 26, it has been observed that when a datagram socket bound to a IPv4 mapped IPv6 address sends a packet, either using the java.net.DatagramSocket or java.nio.channels.DatagramChannel APIs, then the first packet is lost and never gets delivered. A second invocation of send on the same socket, even to the same destination address, correctly delivers the packet and it is received by the recipient.

A bug has been filed with Apple (feedback issue id FB20302424) seeking their assistance. The issue is currently unresolved.

Until the issue is resolved, there are a couple of workarounds that applications can consider:

• If using IPv4 is acceptable, then the java command can be launched with -Djava.net.preferIPv4Stack=true to use IPv4 sockets by default.
• If using -Djava.net.preferIPv4Stack=true is not acceptable, a more local workaround can be applied by changing the application code to create a java.nio.channels.DatagramChannel with java.net.StandardProtocolFamily.INET as the protocol family and then bind the channel to a IPv4 address.

The following root certificates, which are deactivated and no longer in use, have been removed from the cacerts keystore:

+ alias name "affirmtrustcommercialca [jdk]"

  Distinguished Name: CN=AffirmTrust Commercial, O=AffirmTrust, C=US

+ alias name "affirmtrustnetworkingca [jdk]"
  Distinguished Name: CN=AffirmTrust Networking, O=AffirmTrust, C=US

+ alias name "affirmtrustpremiumca [jdk]"
  Distinguished Name: CN=AffirmTrust Premium, O=AffirmTrust, C=US

+ alias name "affirmtrustpremiumeccca [jdk]"
  Distinguished Name: CN=AffirmTrust Premium ECC, O=AffirmTrust, C=US

The XPath processor prevents evaluation of external DTD references in raw XML documents if secure processing is enabled explicitly, such as follows:

XPathFactory xf = XPathFactory.newInstance();

xf.setFeature(XMLConstants.FEATURE_SECURE_PROCESSING, true);

This process will cause the XPath processor created via the factory to throw XPathExpressionException if used to evaluate a raw XML document that contains external references such as an external DTD.

Mitigation includes using External Access Properties to override that enabled by FSP. For example, the following setting will allow the process to continue when there is a reference to a file-based external DTD in the XML document:

xf.setProperty(ACCESS_EXTERNAL_DTD, "file");

It is recommended that applications use the XPath processor to evaluate DOM rather than raw XML documents.

The regression in the serialization of java.time class objects, including LocalDate, has been corrected by backing out the change from JDK-8334742.