In Eclipse Milo versions 0.6.0 through 1.1.4, username-token processing returns distinguishable errors for invalid RSA PKCS#1 v1.5 padding and other authentication failures, allowing an on-path attacker who captures a victim's Basic128Rsa15-encrypted username token to use repeated unauthenticated ActivateSession requests as a padding oracle, recover the victim's password, and authenticate with the recovered credentials.

In Eclipse Milo versions 1.0.0 through 1.1.4, OpcUaServerConfig.copy() fails to preserve a configured RoleMapper. On servers that rely on role permissions and construct the running configuration through copy(), sessions receive no role IDs and the default access controller skips role-permission checks, allowing an anonymous client where anonymous sessions are permitted to read role-permission metadata, invoke protected methods, or delete protected nodes.

In Eclipse Milo versions 0.6.0 through 1.1.4, UASC server transport handlers fail to release retained partial message chunks when a channel disconnects, allowing a remote unauthenticated client to exhaust pooled direct memory by repeatedly sending incomplete chunks and disconnecting, potentially terminating the server.

In Eclipse Milo versions 1.0.0 through 1.1.4, the Call service dispatches the original mixed batch to address-space handlers after calculating authorization, allowing an anonymous or otherwise low-privileged client to execute a denied method by batching it with an allowed method.

A flaw was found in the Eclipse Milo SDK Server. This flaw allows an attacker to consume the application memory, leading to a denial of service by sending specific requests.

In Eclipse Milo versions 1.0.0 through 1.1.4, monitored-item quota accounting is not exception-safe: if item creation fails with an unchecked error, the server-global reservation is not restored. Deeply nested PubSub ExtensionObjects in a CreateMonitoredItems event filter can trigger a StackOverflowError during decoding, allowing an unauthenticated remote client to exhaust a finite global monitored-item quota and prevent all clients from creating new monitored items until restart. Existing monitored items and other server functions remain unaffected.

In Eclipse Milo versions 0.6.0 through 1.1.4, OPC UA server diagnostics nodes do not enforce access authorization. An anonymous client can enable diagnostics over a None/None endpoint without a certificate; with a trusted client application certificate over SignAndEncrypt, it can read security diagnostics for other active sessions, exposing usernames, login history, authentication mechanisms, security modes and policies, and public client certificates.