VulnerabilityDeferred

CVE-2026-45785

There is no cycle detection in TryGetDirectoryEntry, and the bug is reachable from RootStorage.OpenStorage(name), TryOpenStorage(name), OpenStream(name), and TryOpenStream(name), causing an unrecoverable denial of service.

MEDIUM 6.2EPSS 0.18%

Does this matter?

Lower severity and a low EPSS score (0.18%). Track it; it rarely justifies an emergency change on its own.

Description

OpenMcdf is a fully .NET / C# library to manipulate Compound File Binary File Format files, also known as Structured Storage. In 3.1.3 and earlier, 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 every step, drives this while (child is not null) loop forever. There is no cycle detection in TryGetDirectoryEntry, and the bug is reachable from RootStorage.OpenStorage(name), TryOpenStorage(name), OpenStream(name), and TryOpenStream(name), causing an unrecoverable denial of service. This issue is fixed in version 3.1.4.

CVSS 3.1: 6.2 MEDIUMCVSS:3.1/AV:L/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
EPSS: 0.18% probability · 8th percentile
CISA KEV: Not listed
Weakness: CWE-835
Source: security-advisories@github.com

References

Source: NVD record, EPSS from FIRST.org, KEV from CISA. Refreshed daily.