Yes. CISA added CVE-2007-0671 to its Known Exploited Vulnerabilities catalogue on 12 August 2025, which it does only when there is reliable evidence of active exploitation. CISA has not linked it to known ransomware campaigns. Microsoft Office Excel contains a remote code execution vulnerability that can be exploited when a specially crafted Excel file is opened.
What “being exploited in the wild” means for CVE-2007-0671
For a vulnerability like CVE-2007-0671, “exploited in the wild” means there is credible evidence that real attackers are using it outside a lab, proof-of-concept test, or theoretical research setting. That changes the response from routine patch tracking to active exposure management, because exploitation can already be underway when the alert appears.
With this class of Microsoft Office Excel issue, the immediate question is not whether the flaw exists, but whether any user, workstation, or mail gateway can still open a malicious workbook and trigger code execution. If the answer is yes, the organisation has an active delivery path that should be treated as urgent, even if no incident has yet been confirmed internally.
For fast triage, use the Zero-Day and Exploited Vulnerabilities Guide to align KEV status, exploitability, emergency mitigation, and post-patch hunting with the response timeline.
What the Microsoft Excel RCE path changes operationally
Remote code execution in a desktop productivity application matters because the user action is ordinary, opening a file, but the outcome is not. Once the crafted Excel file is opened, the attacker can move from document delivery to code execution on the endpoint, which can then be used for payload staging, persistence, lateral movement, or credential harvesting depending on the broader environment.
That makes exposure broader than the application itself. Endpoints running Excel, mail clients that receive attached workbooks, web proxies that relay downloads, and any business process that depends on spreadsheet exchange can become part of the attack surface. The practical control question is whether the vulnerable workflow still exists anywhere in the estate, not whether Excel is installed somewhere in inventory.
Where the exploit chain is document-led, the response should be tied to Vulnerability Management Guide prioritisation, because KEV-listed issues need faster triage than ordinary backlog remediation.
How to respond when patching or full removal is not immediate
If patching cannot happen immediately, reduce exposure at the delivery and execution layers. The most useful temporary actions are to block or isolate untrusted spreadsheet sources, constrain attachment handling, harden endpoint execution paths, and increase scrutiny on files that arrive through email, chat, or external sharing channels. The goal is to remove the easy delivery route while you work through the permanent fix.
At the same time, assume the environment may already have seen a malicious workbook. Check for suspicious child processes, unusual outbound connections after spreadsheet opens, new persistence points, and unexpected changes in user profile or temp directories. If the organisation handles sensitive data or privileged accounts on affected endpoints, credential reset and session review may be justified as part of compromise assessment.
For authoritative status and remediation timing, cross-check the issue against the CISA Known Exploited Vulnerabilities Catalog and the NIST National Vulnerability Database record for the canonical vulnerability entry and related references.
Risk and Threat Considerations
A publicly exploited Excel RCE combines broad reach with low user friction. Attackers do not need a complex chain if a victim opens a crafted workbook, so the main risk is rapid initial access through a trusted business workflow, followed by whatever post-exploitation activity fits the attacker’s objective.
Failure mechanism: The vulnerability is triggered through normal document handling, which means security controls often see legitimate user behaviour until code execution has already occurred. That can bypass controls that focus only on downloads, web browsing, or known-bad attachments.
Impact: A successful exploit can expose the endpoint to malware installation, credential theft, mailbox access, internal pivoting, and broader compromise if the workstation has access to sensitive resources or shared credentials.
Standards & Framework Alignment
This section maps relevant standards and security frameworks to the operational risks and controls described in this guidance.
CIS Controls v8, NIST SP 800-53 Rev 5 and NIST CSF 2.0 set the governance and control requirements practitioners need to meet.
| Framework | Control / Reference | Relevance |
|---|---|---|
| CIS Controls v8 | CIS-7 — Continuous Vulnerability Management | Exploit-in-the-wild CVE handling depends on rapid prioritization and remediation of known vulnerable software. |
| Recommendation — Prioritize and remediate KEV-listed vulnerabilities immediately across exposed endpoints. | ||
| NIST SP 800-53 Rev 5 | SI-2 — Flaw Remediation | This CVE requires timely patching or mitigation once exploitation is confirmed in the wild. |
| SI-4 — System Monitoring | Exploit activity can be detected through suspicious file-open, process, and network behaviour. | |
| Recommendation — Track, evaluate, and promptly remediate the Excel vulnerability across affected systems. Monitor endpoints for signs of malicious workbook-triggered execution and follow-on activity. | ||
| NIST CSF 2.0 | ID.RA-01 — Asset Vulnerabilities Are Identified and Recorded | Active exploitation makes accurate vulnerability awareness and exposure tracking essential. |
| PR.IR-01 — Networks and Environments Are Protected from Unauthorized Access and Use | Containment and segmentation help limit post-exploitation reach from a compromised endpoint. | |
| Recommendation — Record exposed Excel instances and prioritize the CVE based on confirmed exploitation. Restrict workbook delivery paths and limit what a compromised endpoint can reach. | ||
Practitioner Guidance
What to prioritise: Confirm whether any business unit still opens untrusted Excel files from external sources, then treat those workflows as high-priority exposure points until the vulnerable path is removed or tightly contained.
What to verify: Validate both patch state and post-patch exposure. A fixed version alone is not enough if legacy systems, alternate spreadsheet viewers, cached attachments, or old file-sharing habits still preserve the attack path.
Decision rule: If you cannot patch immediately, compensate by shrinking intake channels, isolating suspect workbooks, and increasing hunt coverage for endpoint compromise. If you already see suspicious process or network activity after spreadsheet opens, escalate as a potential incident rather than a simple vulnerability ticket.
Practitioner takeaway: For a KEV-listed Excel RCE, the real question is whether the file-open path still reaches a live endpoint, because that is what converts a historical CVE into an active enterprise risk.
Related resources from NHI Mgmt Group
- How do you patch or mitigate CVE-2007-0671 (Microsoft Office Excel Remote Code Execution)?
- CVE-2007-0671 (Microsoft Office Excel Remote Code Execution)
- Is CVE-2021-38646 (Microsoft Office Access Connectivity Engine Remote Code Execution) being exploited in the wild?
- Is CVE-2017-0262 (Microsoft Office Remote Code Execution) being exploited in the wild?
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Reviewed and updated by the NHIMG editorial team on October 19, 2026.
NHI Mgmt Group — the #1 independent authority on Non-Human Identity, IAM, and Agentic AI security. nhimg.org