Azure/azure-sdk-for-net Azure.Core_1.63.0

on GitHub

1.63.0 (2026-09-25)

Features Added

• Added mTLS proof-of-possession support to ClientCertificateCredential, including subject name and issuer certificate authentication configured with SendCertificateChain. Proof-of-possession is used by default when requested; first-party applications can opt out by setting the Azure.Identity.EnableClientCertificateMtlsProofOfPossession AppContext switch (or AZURE_IDENTITY_ENABLE_CLIENT_CERTIFICATE_MTLS_POP environment variable) to false.
• Added mTLS proof-of-possession support to the managed identity federated identity flow used by configured credentials, covering both managed identity assertion acquisition and client assertion token redemption. It is enabled by default; set EnableMtlsProofOfPossession to false in the credential's JSON configuration to force bearer authentication for both exchanges. On a host that cannot provide a binding certificate, the flow falls back to a bearer token instead of failing, matching the direct managed identity flow.

Breaking Changes

• Renamed the experimental ManagedIdentityCredentialOptions.DisableMtlsProofOfPossession property and corresponding configuration setting to EnableMtlsProofOfPossession. mTLS proof-of-possession is enabled by default for direct and configured managed identity when requested and supported. To force bearer authentication, replace DisableMtlsProofOfPossession = true with EnableMtlsProofOfPossession = false in code or credential configuration.

Bugs Fixed

• Fixed ModelReaderWriter deserialization of GeoPoint with AzureCoreContext or a generated consumer context throwing because its type builder was not registered.
• Fixed DefaultAzureCredential taking up to a minute to continue past managed identity on hosts where IMDS is unavailable. Ordinary chained requests use the short Azure.Core IMDS probe, while proof-of-possession capability discovery passes the same initial IMDS timeout to MSAL so discovery retry delays are canceled and timed-out discovery results are not cached.
• Fixed chained managed identity aborting the credential chain when MSAL reports all sources unavailable immediately after a successful initial IMDS probe.
• Managed identity mTLS proof-of-possession now requires a KeyGuard-backed host capability and enforces KeyGuard as the minimum binding strength during token acquisition. (#62585)