CVE-2026-107283: AsyncHttpClient: Digest authentication cnonce generated with a non-cryptographic random source

The client nonce used in HTTP Digest authentication was generated from ThreadLocalRandom, a fast but non-cryptographic pseudorandom number generator. RFC 7616 section 3.3 requires the cnonce to be unpredictable, since it is part of what protects the Digest exchange against chosen-plaintext and precomputation attacks on the credentials. An attacker able to observe or influence enough of the generator’s output could reduce the unpredictability the protocol depends on. NTLM (and, on the 3.x line, SCRAM) in this client already use SecureRandom for their own nonces; Digest did not.