Infinite loop Affecting openmcdf package, versions [,3.1.4)
Threat Intelligence
Snyk has a proof-of-concept or detailed explanation of how to exploit this vulnerability.
The probability is the direct output of the EPSS model, and conveys an overall sense of the threat of exploitation in the wild. The percentile measures the EPSS probability relative to all known EPSS scores. Note: This data is updated daily, relying on the latest available EPSS model version. Check out the EPSS documentation for more details.
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Test your applications- Snyk IDSNYK-DOTNET-OPENMCDF-16770142
- published20 May 2026
- disclosed13 May 2026
- creditPaweł Łukasik
Introduced: 13 May 2026
CVE-2026-45785 (opens in a new tab)How to fix?
Upgrade OpenMcdf to version 3.1.4 or higher.
Overview
OpenMcdf is a fully .NET / C# library to manipulate Compound File Binary File Format files, also known as Structured Storage.
Affected versions of this package are vulnerable to Infinite loop involving the TryGetDirectoryEntry() function, which is accessible via RootStorage.OpenStorage() and RootStorage.OpenStream(). An attacker can cause a thread to enter an uncaught and unrecoverable loop by providing a malicious CFB file with cyclic sibling directory entries. Cycles are properly detected for DirectoryTreeEnumerator, but individual entry lookups are vulnerable to the pattern described here.
PoC
using OpenMcdf;
using var fs = File.OpenRead("repro_enumerate.cfb");
using var root = RootStorage.Open(fs);
foreach (var entry in root.EnumerateEntries()) // safe: Brent's catches enumeration cycles
{
if (entry.Type == EntryType.Stream)
_ = root.OpenStream(entry.Name); // hangs: lookup path has no cycle detection
}