Security readout for executives and security teams
Plain-English summary
This is a Microsoft Excel remote code execution flaw. A successful attack requires user interaction and could let attacker-controlled code run with high impact to confidentiality, integrity, and availability. Microsoft lists an official fix; no provided source shows active exploitation.
Executive priority
Treat as a high-priority patching item for Office environments, especially where users handle outside documents. It is not supported by supplied evidence as actively exploited, but the impact of successful code execution is material.
Technical view
CVE-2023-33158 is rated CVSS 7.8 with AV:L/AC:L/PR:N/UI:R and impacts multiple Microsoft Office/Excel product lines. The bundle maps it to CWE-191, an integer underflow class. Remediation level is official fix, and exploit maturity is unproven in the supplied data.
Likely exposure
Organizations using the listed Microsoft Office 2019 for Mac, Microsoft 365 Apps for Enterprise, Office LTSC for Mac 2021, Office LTSC 2021, or Office for Universal versions should assume possible exposure until patched status is verified.
Exploitation context
The provided data requires user interaction and does not show KEV listing or confirmed active exploitation. The sources do not provide exploit details, public weaponization evidence, or a safe standalone detection method.
Researcher notes
The public bundle is sparse: it confirms product scope, CVSS, CWE-191, official fix availability, and no KEV signal. Avoid claiming exploitation or specific attack mechanics without additional vendor or threat intelligence evidence.
Mitigation direction
- Apply the official Microsoft update referenced by the MSRC advisory.
- Inventory affected Office and Excel installations across managed endpoints.
- Prioritize users handling spreadsheets from external or untrusted sources.
- Check Microsoft guidance for any environment-specific mitigations or update channels.
- Keep endpoint protection and attachment controls active while patching completes.
Validation and detection
- Confirm installed Office products match or exceed Microsoft’s fixed versions.
- Verify patch compliance through endpoint management or software inventory records.
- Check whether any listed affected product remains on unpatched channels.
- Review security tooling for Excel-related alerts around the disclosure window.
- Document exceptions and compensating controls for systems awaiting updates.
Public sources used
Generated from the cited source records. This long-tail analysis has not been individually reviewed by a named human.
Conservative CVE-to-ATT&CK context
These mappings and lookup hints may be relevant to the vulnerability behavior, CWE, affected product, or exposure path. Glexia-inferred context is not an official MITRE, ATT&CK, CWE, or CVE Program mapping.
ATT&CK lookup starting points
Use these exact CWE pages and searches to review the Glexia ATT&CK library from this CVE's weakness and description context.
CWE-191: Exact CWE lookup
Use the exact CWE identifier as the starting point before reviewing related ATT&CK behavior. Open the exact CWE lookup page first, then review the ATT&CK searches from that MITRE weakness context. This is a Glexia lookup hint, not an official ATT&CK mapping.
Open ATT&CK lookupExecution behavior lookup
The CVE wording references code or command execution, so execution technique review may help defensive triage. This is a Glexia inferred lookup path, not an official MITRE, ATT&CK, or CVE Program mapping.
Open ATT&CK lookupCVE-2023-33158 mapping review
Open the CVE-to-ATT&CK bridge for reviewed, inferred, or future official mappings tied to this CVE.
Open ATT&CK lookup- Severity
- High
- CVSS
- 7.8 (3.1)
- Known Exploited
- No
- Published
Vector: CVSS:3.1/AV:L/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H/E:U/RL:O/RC:C
CNA and ADP enrichment extracted from CVE v5
These fields come from the CVE record and ADP containers, not from Glexia's Take. They preserve time-varying source decisions such as CISA SSVC, KEV status, CVSS metrics, and provider references.
CVSS vector scores
1 official scoreWe collect every scored CVSS vector available in the official CNA and ADP containers. When more than one version is present, the table keeps the source vectors side by side instead of collapsing them into the highest score.
CVSS:3.1/AV:L/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H/E:U/RL:O/RC:C1.85.9Primary CVE scoreVulnerability scoring details
Base CVSS 3.1 score
7.8HighVector: CVSS:3.1/AV:L/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H/E:U/RL:O/RC:C
Source materials
- CVE List V5 sourceCVE List V5
- Microsoft Excel Remote Code Execution VulnerabilityCVE reference · vendor-advisory
Products and packages named in the record
CWE details
CWE links open Glexia weakness intelligence pages with official CWE context, developer remediation guidance, and related CVE mappings.
Integer Underflow (Wrap or Wraparound)
Integer Underflow (Wrap or Wraparound) represents a recurring weakness pattern that can create exploitable paths when design, validation, or implementation controls are missing.