OpenMcdf: Uncatchable infinite loop in DirectoryTree.TryGetDirectoryEntry on crafted CFB directory cycle

MITRE NVD CVE.ORG JSON API

Summary

CVECVE-2026-45785
StatePUBLISHED
AssignerGitHub_M
Source PriorityCVE Program / NVD first with legacy fallback
Published2026-07-17 21:17:06 UTC
Updated2026-07-21 04:16:50 UTC
DescriptionOpenMcdf 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.

Risk And Classification

Primary CVSS: v3.1 6.2 MEDIUM from [email protected]

CVSS:3.1/AV:L/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H

EPSS: 0.001290000 probability, percentile 0.029810000 (date 2026-07-21)

Problem Types: CWE-835 | CWE-835 CWE-835: Loop with Unreachable Exit Condition ('Infinite Loop')

VersionSourceTypeScoreSeverityVector
3.1[email protected]Secondary6.2MEDIUMCVSS:3.1/AV:L/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
3.1CNADECLARED6.2MEDIUMCVSS:3.1/AV:L/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H

CVSS v3.1 Breakdown

Attack Vector
Local
Attack Complexity
Low
Privileges Required
None
User Interaction
None
Scope
Unchanged
Confidentiality
None
Integrity
None
Availability
High

CVSS:3.1/AV:L/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H

Vendor Declared Affected Products

SourceVendorProductVersionPlatforms
CNA Openmcdf Openmcdf affected < 3.1.4 Not specified

References

ReferenceSourceLinkTags
github.com/openmcdf/openmcdf/security/advisories/GHSA-5qwm-7pvp-w988 134c704f-9b21-4f2e-91b3-4a467353bcc0 github.com
github.com/openmcdf/openmcdf/releases/tag/v3.1.4 [email protected] github.com
github.com/openmcdf/openmcdf/commit/c6f82db722bd85db7b0caed3ca1aa374f1e0... [email protected] github.com
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