CVE-2018-0802 is a memory corruption vulnerability in Microsoft Office. CISA added it to the Known Exploited Vulnerabilities catalogue on 3 November 2021, which means attackers have used it in real attacks. Microsoft Office contains a memory corruption vulnerability due to the way objects are handled in memory. This vulnerability is known to be chained with CVE-2018-0798.
How This Vulnerability Behaves in Microsoft Office
This is a memory corruption flaw, so the core issue is not a policy misconfiguration but unsafe handling of in-memory objects inside a widely targeted productivity suite. When that kind of bug is reachable from a document or content trigger, it can turn routine file opening into an execution path for malicious code.
In practice, that makes the vulnerability especially dangerous because Microsoft Office is often trusted, broadly deployed, and used to process externally supplied files. Attackers do not need to convince a user to install a rogue application if they can instead weaponise content that Office is expected to parse.
Why Chaining Makes It More Dangerous
The primary definition states that this issue is known to be chained with CVE-2018-0798. Chaining matters because one flaw may provide the initial trigger while the other helps complete the exploitation path, increasing the chance that an otherwise partial bug becomes a reliable compromise route.
That pattern is common in real-world exploitation: the first stage may create memory safety corruption, then a second issue or exploit technique turns that corruption into code execution or a more stable foothold. For defenders, the important point is that the risk is not only the single CVE in isolation, but the combined attack path an adversary can assemble.
How Organisations Check Exposure and Limit Blast Radius
Exposure review should start with a precise inventory of where Microsoft Office is installed, which endpoints still process untrusted documents, and which systems are internet-facing or otherwise likely to receive external files. For version and remediation guidance, readers should rely on the vendor advisory and the NIST National Vulnerability Database, alongside the CVE Program record for the exact identifier.
Compensating controls matter when patching is delayed. Restricting attachment handling, limiting macro-enabled workflows, separating high-risk document processing from privileged workstations, and reducing internet-reachable exposure all help narrow the window in which exploitation can succeed. A broader Vulnerability Management Guide is useful for prioritising this kind of active KEV-listed issue against asset scope and remediation urgency.
Detection, Response, and Identity Impact After Exploitation
Because exploited memory corruption often leads to code execution or post-exploitation activity, detection should look beyond the initial document event and into the follow-on process chain, unusual child processes, suspicious network access, and persistence behaviour. If exploitation is suspected, organisations should review whether the affected user session, tokens, or any credentials exposed on that endpoint were captured or misused.
That review becomes more important when Office runs in environments with access to email, file shares, cloud storage, or administrative tooling. Even a single successful exploit can become a launch point for lateral movement, so post-incident scoping should include both endpoint compromise and any downstream access that the user or host could reach.
Risk and Threat Considerations
Microsoft Office vulnerabilities are high-value targets because they sit on a common trust path: users open files, Office renders content, and the application processes complex objects at scale. A memory corruption flaw in that path can enable remote code execution, document-based delivery, and rapid spread through routine business workflows.
Failure mechanism: attacker-controlled content reaches the vulnerable parsing or object-handling logic, corrupts memory, and creates an execution primitive that can be chained into compromise.
Impact: successful exploitation can lead to malware execution, endpoint compromise, follow-on credential theft, and movement into adjacent systems that the workstation can access.
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 CSF 2.0, OWASP ASVS and NIST SP 800-53 Rev 5 set the governance and control requirements practitioners need to meet.
| Framework | Control / Reference | Relevance |
|---|---|---|
| CIS Controls v8 | CIS-7 — Continuous Vulnerability Management | This CVE is an actively exploited flaw that needs prioritised exposure tracking and remediation. |
| Recommendation — Prioritise and remediate the affected Office exposure using continuous vulnerability management and KEV-aware triage. | ||
| NIST CSF 2.0 | ID.RA-01 — Asset vulnerabilities are identified and documented | Exposure assessment for this Office CVE depends on knowing where the vulnerable software exists. |
| PR.IP-12 — A vulnerability management plan is developed and implemented | Known exploited vulnerabilities require an organised remediation process, not ad hoc fixes. | |
| Recommendation — Identify affected Office assets and document the vulnerable exposure before assigning remediation priority. Use a vulnerability management plan to drive patching, compensating controls, and verification for the Office flaw. | ||
| OWASP ASVS | V13 — Configuration | Document-triggered exploitation risk is reduced when dangerous Office features and trust settings are constrained. |
| Recommendation — Harden document-handling and feature settings to reduce the attack surface available to malicious files. | ||
| NIST SP 800-53 Rev 5 | SI-2 — Flaw Remediation | An exploited memory corruption vulnerability requires formal flaw remediation and verification. |
| SI-3 — Malicious Code Protection | This exploit path can deliver malicious code through documents and needs layered code-execution defenses. | |
| Recommendation — Patch the affected Office software promptly and verify remediation after deployment. Apply malicious code protections to block or contain payloads delivered through Office documents. | ||
Practitioner Guidance
What to watch for: treat this as a patch-priority issue where Office is exposed to untrusted content, especially on user endpoints that handle external email, downloaded files, or shared documents. If you cannot remediate immediately, reduce exposure by constraining document sources and limiting the blast radius of the systems that open them.
Practitioner takeaway: for an actively exploited Office memory corruption issue, the decisive question is not whether users can open documents, but whether a compromised document path can still reach a privileged or business-critical endpoint.
Related resources from NHI Mgmt Group
Deepen Your Knowledge
Free weekly newsletter
Subscribe to the NHI & AI Identity Journal
The latest on NHI and Agentic AI security – articles, research, breaches, news and events every week.
Bonus 33% off our NHI Course when you subscribe.
Reviewed and updated by the NHIMG editorial team on October 17, 2026.
NHI Mgmt Group — the #1 independent authority on Non-Human Identity, IAM, and Agentic AI security. nhimg.org