The Bluetooth host ATT layer (subsys/bluetooth/host/att.c) associates each in-flight ATT TX buffer with its owning channel via the static tx_meta_data_storage[] array (data->att_chan = chan). When a buffer's last reference is dropped, its net-buf destroy callback defers the completion handling to the system workqueue (att_tx_destroy -> att_tx_destroy_work_handler -> att_on_sent_cb -> bt_att_sent), where bt_att_sent dereferences the channel and its ATT context (sys_slist_get(&att->reqs)).
When a peer disconnects while an ATT PDU (a server notification/indication or any response) is still in flight in the controller TX path, L2CAP tears the channel down in l2cap_chan_del(): it runs the disconnected callback and then the released callback (bt_att_released), which frees the channel slab slot. Because the in-flight buffer is held by the connection TX path rather than the channel's own queue, its deferred destroy work can run after the channel has been freed. The att_on_sent_cb guard intended to drop the stale callback itself dereferences meta->att_chan, which is now a dangling pointer into a freed (and possibly reused) slab slot.
A remote peer with an ATT connection can drive this by disconnecting during routine ATT traffic; no pairing or user interaction is required to reach the ATT bearer. The result is a use-after-free read/write of freed channel memory, reliably crashing the Bluetooth host (denial of service) and, because the channel slab slot may be reused, potentially corrupting live memory.
The fix makes bt_att_released() NULL the att_chan field of every tx_meta_data_storage[] entry still referencing the channel before freeing it, so the deferred guard observes a NULL pointer and drops the callback. Teardown and the destroy work both run on the cooperative system workqueue, so the array update is serialized and needs no lock.
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, 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, 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 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.
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.
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 Jetty, the Digest authentication server-side component uses ISO-8859-1 to encode the password as bytes.
This was done because the initial specification for HTTP did not specify explicitly a charset, and it was assumed to be ISO-8859-1 for historical reasons.
If the password contains characters that cannot be represented in ISO-8859-1, they are silently replaced by `?`. This happens with passwords that contain Chinese, Cyrillic or Greek characters, for example: `αβ123` converts to `??123`.
An attacker can send a request with a digest `Authorization` header crafted with a password made of only `?` characters; the server would match any password of the same length that contains non-ISO-8859-1 characters.
Recent HTTP Digest [RFC-7616](https://datatracker.ietf.org/doc/html/rfc7616) supports a `charset` parameters that defaults to UTF-8 that allows for correct encoding/decoding of passwords.