Security readout for executives and security teams
Plain-English summary
This critical Microsoft Word flaw could allow a remote attacker to run code without credentials or user interaction, according to its CVSS assessment. Successful exploitation could seriously affect data confidentiality, integrity, and system availability. Organizations using the listed Office, Word, SharePoint, or Office server products should verify and patch affected installations promptly.
Executive priority
Treat remediation as an urgent patching initiative because the vulnerability combines remote code execution with a 9.8 severity score and broad Office and server exposure. Require rapid inventory, vendor-update deployment, and documented exceptions. The evidence does not establish active exploitation, so communicate urgency without claiming an ongoing campaign.
Technical view
CVE-2023-21716 is a remote code execution vulnerability associated with integer overflow, CWE-190. It carries CVSS 3.1 score 9.8: network-accessible, low complexity, no privileges, and no user interaction, with high confidentiality, integrity, and availability impact. The supplied evidence does not describe the vulnerable component or exploitation mechanism.
Likely exposure
Exposure includes listed Microsoft 365 Apps, Office 2019, Office LTSC 2021, Word 2013 and 2016, Office Online Server, Office Web Apps Server 2013, and multiple SharePoint editions. Actual risk depends on whether affected versions are installed, reachable, and missing the applicable Microsoft security update.
Exploitation context
The supplied bundle marks this CVE as absent from KEV and provides no cited evidence of active exploitation. That does not prove exploitation has never occurred. The CVSS vector indicates a potentially remote, low-complexity attack requiring neither privileges nor user interaction, but the sources provided do not document a working exploit or observed campaigns.
Researcher notes
The record identifies CWE-190 and a critical CVSS vector but does not explain the vulnerable parsing path, attack delivery, affected build ranges, indicators, or detection logic. Product entries include both desktop and server software. Consult Microsoft’s advisory for authoritative update mapping; avoid inferring exploitability details beyond the supplied CVSS and affected-product data.
Mitigation direction
- Review Microsoft’s advisory for exact product-specific security updates and deployment requirements.
- Apply applicable Microsoft updates across every affected Office, Word, SharePoint, and Office server installation.
- Prioritize reachable servers and systems handling untrusted content or supporting high-risk users.
- If patching is delayed, obtain Microsoft-approved mitigations; none are specified in the supplied evidence.
Validation and detection
- Inventory installed products and versions against every affected product listed in the CVE record.
- Use Microsoft’s advisory to identify the exact update applicable to each installation.
- Confirm installed builds or updates match Microsoft guidance after deployment.
- Re-scan the environment and document affected systems that remain unpatched or require exceptions.
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-190: 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-2023-21716 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
- Critical
- CVSS
- 9.8 (3.1)
- Known Exploited
- No
- Published
Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/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:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H/E:U/RL:O/RC:C3.95.9microsoftVulnerability scoring details
Base CVSS 3.1 score
9.8CriticalVector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/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 Word 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.
Integer Overflow or Wraparound
Integer Overflow or Wraparound represents a recurring weakness pattern that can create exploitable paths when design, validation, or implementation controls are missing.