CVE-2026-41511: OpenMcdf is a fully .NET / C# library to manipulate Compound File Binary File Format files, also known as Stru

Q: How do I fix CVE-2026-41511?

openmcdf: upgrade to 3.1.3. Exact commands for each OS are on this page.

Q: Is CVE-2026-41511 being exploited?

CVE-2026-41511 is not on the CISA Known Exploited Vulnerabilities list at the time of the last update. Check again, as this can change.

Q: What does CVE-2026-41511 affect?

CVE-2026-41511 affects openmcdf. Severity is medium (CVSS 6.2). 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 B

Q: How urgent is CVE-2026-41511?

Priority 29/100. Public exploit reference

Routine

MEDIUM 6.2UPGRADE

CVE-2026-41511 is a medium-severity flaw (CVSS 6.2) affecting openmcdf. Below: why it ranks where it does, which versions are affected, what to do, and the exact commands.

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 wi

Why this priority

Public exploit reference

A fixed release or distro patch exists.

Risk facts

CVSS score	6.2 (Medium)
Attack vector	Local
Attack complexity	Low
Privileges needed	None
User interaction	None
EPSS exploit chance	0.2% (top 92%)
CISA exploited list	No
Weakness	CWE-835
Published	2026-05-08
Last modified	2026-10-26

Publisher (CNA): GitHub, Inc. · Vendor: openmcdf

Last updated 2026-10-26 · Sources: CVE Program, NVD, CISA KEV, EPSS and vendor advisories · How we score

Am I affected?

Timeline

2026-05-08 19:16 UTCPublished CVE record published
2026-10-26 18:10 UTCUpdated Record last modified

openmcdf openmcdf UPGRADE

Affected: < 3.1.3

Fixed in: 3.1.3

Safe to downgrade to: no unaffected older release

1. Check installed version

apt-cache policy openmcdf || rpm -q openmcdf || openmcdf --version

2. UPGRADE to 3.1.3 (Debian / Ubuntu)

sudo apt update && sudo apt install --only-upgrade openmcdf

2. UPGRADE (RHEL / Amazon Linux / Fedora)

sudo dnf upgrade openmcdf

Note

Distros often backport fixes without changing the version number. Confirm with the distro advisory or changelog.

Verify at the official source NVD · CVE Program · Report a problem with this page
Scores and fixes here are computed automatically from those and other public sources. Confirm with the vendor advisory before changing production systems.

Quick answers

How do I fix CVE-2026-41511?

openmcdf: upgrade to 3.1.3. Exact commands for each OS are on this page.

Is CVE-2026-41511 being exploited?

CVE-2026-41511 is not on the CISA Known Exploited Vulnerabilities list at the time of the last update. Check again, as this can change.

What does CVE-2026-41511 affect?

CVE-2026-41511 affects openmcdf. Severity is medium (CVSS 6.2). 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 B

How urgent is CVE-2026-41511?

Priority 29/100. Public exploit reference

References

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