What is the CVSS score of CVE-2026-44822?

CVE-2026-44822 has a CVSS 3.1 base score of 8.2 (High). CVSS vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:L/A:N. EPSS exploitation probability: 0.1%.

Which versions of Microsoft Excel are affected by CVE-2026-44822?

Microsoft Office Excel contains an unauthenticated network-based information disclosure vulnerability (CVE-2026-44822, CVSS 8.2) that extracts sensitive data from process memory without user…. A patch is available.

How to fix or mitigate CVE-2026-44822?

Within 24 hours: Audit and inventory all Excel installations; isolate high-risk systems processing sensitive data. Within 7 days: Implement network segmentation restricting Excel system internet connectivity; disable external document sharing and remote file access in Excel group policies; activate endpoint detection and response (EDR) monitoring for anomalous Excel process network activity. Within 30 days: Subscribe to Microsoft security bulletins for CVE-2026-44822 patch status; prepare expedited deployment process for when vendor releases fix; evaluate alternative productivity tools with mitigation controls for critical workflows.

Microsoft Excel CVE-2026-44822

EUVD-2026-35537 HIGH

Out-of-bounds Read (CWE-125)

2026-06-09 secure@microsoft.com

GHSA-whhp-jpfm-6hhm

Information Disclosure Microsoft Buffer Overflow 365 Apps Excel Microsoft 365 Office 2019 Office 2021 Office 2024 Office Online Server

8.2

CVSS 3.1 · Vendor: microsoft

Temporal: 7.1

Severity by source

Vendor (microsoft) PRIMARY

8.2 HIGH

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

CIRCL (temporal)

7.1 HIGH

cvss

Primary rating from Vendor (microsoft).

CVSS VectorVendor: microsoft

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

Attack Vector

Network

Attack Complexity

Low

Privileges Required

None

User Interaction

None

Scope

Unchanged

Confidentiality

High

Integrity

Low

Availability

None

Lifecycle Timeline

Patch available

Jun 09, 2026 - 19:03 EUVD

Analysis Generated

Jun 09, 2026 - 18:29 vuln.today

CVE Published

Jun 09, 2026 - 17:17 nvd

HIGH 8.2

DescriptionCVE.org

Out-of-bounds read in Microsoft Office Excel allows an unauthorized attacker to disclose information over a network.

AnalysisAI

Information disclosure in Microsoft Office Excel allows remote unauthenticated attackers to read out-of-bounds memory over a network, potentially exposing sensitive data from process memory. The CVSS 8.2 score reflects high confidentiality impact with no authentication or user interaction required per the CVSS vector. No public exploit identified at time of analysis and the vulnerability is not currently listed in CISA KEV.

Technical ContextAI

The vulnerability stems from CWE-125 (Out-of-bounds Read), a memory safety class in which the application reads data past the bounds of an allocated buffer, returning adjacent process memory contents to the attacker. In Microsoft Excel this typically occurs during parsing of a malformed spreadsheet structure (record, formula, stream, or embedded object) where length or offset fields are not properly validated against the actual buffer size. Excel's file format parsers (XLS/XLSX/XLSB and related OLE/OOXML structures) handle a wide variety of binary records, and a missing bounds check on one of these fields permits the parser to disclose heap or stack memory contents back to attacker-controlled output paths.

RemediationAI

Patch available per vendor advisory - apply the security update referenced on the MSRC page at https://msrc.microsoft.com/update-guide/vulnerability/CVE-2026-44822 for the affected Excel channel and build as soon as it is available through Windows Update, Microsoft Update, or your enterprise patch management system; exact fix build numbers were not supplied in this dataset and should be confirmed against the MSRC entry. As compensating controls until patching, enable Protected View and Application Guard for Office for files originating from the internet or email (trade-off: users may need to explicitly enable editing for trusted documents), block or quarantine inbound .xls/.xlsx/.xlsb attachments at the mail gateway from untrusted senders, disable legacy binary Excel formats via Group Policy 'File Block Settings' if business workflows allow (trade-off: breaks workflows that depend on legacy formats), and consider Attack Surface Reduction rules that block Office from creating child processes to limit chaining potential. The VulDB entry at https://vuldb.com/vuln/369658 may carry additional indicator or detection guidance.