What’s Vulnerable › Vulnerabilities

CVE-2026-41511: OpenMcdf has an Infinite loop DoS via crafted CFB directory cycle

• Severity: medium (CVSS 5.5 v3.1)
• Exploited in the wild: not listed in CISA KEV
• EPSS: 0.2% probability of exploitation in the next 30 days
• Public exploit or detection template: yes
• Published: 2026-05-08 · updated 2026-10-26
• Weakness: CWE-835

Description

OpenMcdf is a fully .NET / C# library to manipulate Compound File Binary File Format files, also known as Structured Storage. Prior to version 3.1.3, OpenMcdf does not detect cycles in the directory entry red-black tree of a Compound File Binary (CFB) document. A crafted CFB file with a cycle in the LeftSiblingID / RightSiblingID chain causes Storage.EnumerateEntries() and Storage.OpenStream() to loop indefinitely, consuming the calling thread with no possibility of recovery via try/catch. This issue has been patched in version 3.1.3.

Affected products

• openmcdf: before 3.1.3 — fixed in 3.1.3

How to fix

Upgrade to a fixed version: openmcdf 3.1.3. Check the vendor advisory for mitigations.

References

• https://github.com/openmcdf/openmcdf/commit/24f445a557fc4f46461cf6d02d296cce16c293a0
• https://github.com/openmcdf/openmcdf/releases/tag/v3.1.3
• https://github.com/openmcdf/openmcdf/security/advisories/GHSA-jxpf-xq2m-q525
• https://github.com/openmcdf/openmcdf/security/advisories/GHSA-jxpf-xq2m-q525

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