CVE-2023-33162 Microsoft CVE debrief

Who should care

Organizations running affected Microsoft Office versions in environments where users open Excel documents from external or untrusted sources should prioritize remediation. Security teams responsible for endpoint protection, patch management administrators, and IT operations supporting document-intensive workflows are the primary stakeholders. Organizations with compliance requirements for data confidentiality should assess exposure, particularly those in regulated industries handling sensitive financial, healthcare, or personal data in Excel formats.

Technical summary

This vulnerability exists in Microsoft Excel and can result in information disclosure when a user opens a specially crafted file. The attack requires local access and user interaction, with the attacker able to read sensitive information from memory. The vulnerability stems from an out-of-bounds read condition (CWE-125) in Excel's file parsing components. Affected products span multiple Office versions and deployment architectures, including legacy Office 2013 SP1 through current Office LTSC 2021 and Microsoft 365 Apps Enterprise channels. The vulnerability does not affect integrity or availability, but the high confidentiality impact rating indicates significant potential for sensitive data exposure.

Defensive priority

medium

Recommended defensive actions

• Apply Microsoft security updates for affected Office and Microsoft 365 Apps installations as provided in the Microsoft Security Response Center guidance
• Prioritize patching systems where Excel files from untrusted sources are regularly processed
• Review and restrict macro execution policies and document opening behaviors for files originating from external sources
• Monitor for anomalous Excel process behavior that may indicate exploitation attempts
• Ensure Office installations are configured for automatic updates where organizational policy permits

Evidence notes

The vulnerability is classified as an information disclosure issue with CVSS vector AV:L/AC:L/PR:N/UI:R/S:U/C:H/I:N/A:N, indicating local attack vector, low attack complexity, no privileges required, user interaction required, unchanged scope, high confidentiality impact, and no integrity or availability impact. The weakness is associated with CWE-125 (Out-of-bounds Read) per Microsoft, though NVD lists it as NVD-CWE-noinfo.

Sources and references

Methodology and review provenance

AI-assisted synthesis based on stored public vulnerability evidence. System validation, approval state, and publication status do not by themselves establish human review of this revision. PatchSiren helps prioritize defensive review and does not prove exposure or remediation on any system.