Security readout for executives and security teams
Plain-English summary
A flaw in Microsoft Excel can let an attacker run code after a user interacts with affected Office software. Successful exploitation could compromise the confidentiality, integrity, and availability of the user’s system. The issue is rated high severity, not critical, because user interaction and local execution context are required.
Executive priority
Treat this as a high-priority patching item. Code execution could enable full compromise of an affected user context, but available evidence does not show active exploitation. Prioritize exposed users and systems that regularly process externally sourced spreadsheets, then complete broad deployment according to Microsoft’s guidance.
Technical view
CVE-2026-45469 is an integer-underflow vulnerability associated with CWE-191 and CWE-122. Microsoft reports that it can lead to local code execution without prior privileges. CVSS 3.1 rates it 7.8: low complexity, no privileges required, user interaction required, unchanged scope, and high impact across confidentiality, integrity, and availability.
Likely exposure
Exposure includes the listed Microsoft 365 Apps, Excel 2016, Office 2019, Office LTSC 2021 and 2024, corresponding Mac editions, and Office Online Server. The supplied version values may identify product families rather than precise vulnerable build ranges; confirm applicability against Microsoft’s advisory and local build inventory.
Exploitation context
The supplied record does not establish active exploitation. It is not listed in KEV, and the CVSS exploit-maturity value is unproven. Exploitation requires user interaction and uses a local attack vector, but the sources do not specify the exact delivery method or exploitation chain.
Researcher notes
The record identifies integer underflow and heap-based buffer-overflow weakness classes but does not document the vulnerable component, triggering file structure, memory-corruption sequence, patch identifiers, or exact fixed builds. Researchers should avoid inferring these details and use Microsoft’s advisory for product-specific applicability and remediation evidence.
Mitigation direction
- Review Microsoft’s CVE advisory for applicable security updates and exact affected builds.
- Deploy the applicable Microsoft updates through normal endpoint and server patch processes.
- Prioritize systems handling externally supplied or untrusted Excel content.
- Apply organizational controls for suspicious Office files while patching is completed.
Validation and detection
- Inventory installed Office, Excel, Microsoft 365 Apps, Mac, and Office Online Server versions.
- Compare installed build and update levels with Microsoft’s CVE advisory.
- Verify applicable security updates installed successfully across managed endpoints and servers.
- Investigate update failures and remaining vulnerable installations through endpoint-management reporting.
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-122: 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 lookupCWE-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-2026-45469 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.
SSVC decision data
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:C1.85.9microsoftVulnerability 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
Vulnerability timeline
Timeline events are normalized from CVE metadata, CNA source timelines, ADP timelines, and KEV metadata when present.
- CVE reservedCVE Program
The CVE ID was reserved by the assigning CNA.
- CVE publishedCVE Program
The CVE record was published.
- CVE updatedCVE Program
The CVE record metadata indicates this as the latest update time.
ADP provider summaries
Source materials
- CVE List V5 sourceCVE List V5
- Microsoft Excel Remote Code Execution VulnerabilityCVE reference, microsoft · vendor-advisory, patch
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.
Heap-based Buffer Overflow
Heap-based Buffer Overflow represents a recurring weakness pattern that can create exploitable paths when design, validation, or implementation controls are missing.
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.