OpenMcdf: Uncatchable infinite loop in DirectoryTree.TryGetDirectoryEntry on crafted CFB directory cycle — CVE-2026-45785

Summary

### Summary The BST name-lookup loop in `DirectoryTree.TryGetDirectoryEntry` (`OpenMcdf/DirectoryTree.cs:35-46`) walks directory entries by repeatedly calling `directories.TryGetSibling(child, siblingType, validateColor)`. A crafted CFB file with cyclic Left/Right sibling links among directory entries - constructed so the per-step BST-order check in `TryGetSibling` (`DirectoryEntries.cs:84-85`) is satisfied at…

Product

nuget: OpenMcdf

What to do

General, cautious steps (verify details in the official source):

• Review exposure and plan remediation based on risk and environment.
• Identify affected product versions in your inventory and verify whether you are impacted.
• Apply vendor patches/updates or recommended mitigations as soon as available.
• Read the official advisory for exact affected versions and remediation steps.

Official advisory

• Read the official source
• CVE Record
• NVD

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