What does HRESULT 0x8009002B (NTE_BUFFERS_OVERLAP) mean?

NTE_BUFFERS_OVERLAP

NTE_BUFFERS_OVERLAP identifies a failure in input/output aliasing. The provider detected source and destination memory ranges that overlap in a way the selected cryptographic operation does not permit. Diagnose input/output aliasing at the first component that returned the value, not the last user-interface layer that displayed it; later cleanup and fallback attempts can produce different secondary errors.

Locate the first failing stage

Many Windows cryptographic APIs use caller-owned byte buffers with exact sizing and aliasing rules. Capacity, byte-versus-character units, two-pass size queries, padding expansion, and permitted in-place layouts all belong to the call contract. Inspect address ranges and lengths, not just pointer equality or a nominal array size.

Useful observations, not generic logs

• Input and output base addresses, byte lengths, and the range each one occupies
  Calculate byte ranges, not only pointer equality, for every input and output buffer.
  Distinguishes byte capacity from address-range overlap.
• The size returned by a query pass and every parameter that changed before the data pass
  Check in-place operation support for the exact algorithm, mode, padding, and provider.
  Detects stale lengths after parameters or key state changed.
• Algorithm, mode, padding, tag, property, and provider-specific in-place rules
  Use separate buffers or a documented in-place layout, then keep the original input available for comparison.
  Shows whether the provider supports the proposed in-place layout.

What to include in an escalation package

• A known-good control result produced under the same identity, architecture, and provider selection.

Reproduction without destructive cleanup

Allocate distinct input and output buffers from the latest size returned by the same key and parameter set. Preserve the original input, call the operation once, and compare reported lengths. Then test in-place behavior only when the API explicitly documents it in an input/output aliasing investigation.

1. Use one known-good control that changes only the suspected part of the input/output aliasing path.
2. Record where behavior first diverges in the input/output aliasing path instead of judging only by the final application message.

How this differs from similar failures

A buffer may be large enough and still fail here. NTE_BUFFER_TOO_SMALL addresses capacity; this code addresses memory layout. A larger buffer does not cure forbidden overlap, and separate buffers do not cure insufficient capacity. Keep those hypotheses separate so a test does not accidentally change both conditions.

For input/output aliasing, also retain the original numeric value; neighboring constants can encode materially different remediation paths even when an application presents all of them as an authentication, certificate, or security failure.

Regression check

Resolution requires correct byte ranges and sizes for the exact algorithm and provider, including repeated calls where output length varies with padding or encoded content.

Technical references

These sources define the HRESULT and the relevant input/output aliasing interface, protocol, or data format.

• Microsoft Open Specifications: HRESULT values.
• Microsoft: CNG key storage functions.
• Microsoft: CNG primitive cryptography functions.