Security Digest · Vulnerability record · Known exploited
CVE-2026-21514: Microsoft Office Word Reliance on Untrusted Inputs in a Security Decision Vulnerability
Exploited in the wild (CISA KEV). Reliance on untrusted inputs in a security decision in Microsoft Office Word allows an unauthorized attacker to bypass a security feature locally.
CISA KEV · added 2026-02-10 CVSS 7.8 High EPSS 1.6% · p75
Should you act?
Exploited: patch now if you run it
CISA has confirmed exploitation in the wild. This signal is computed from CISA KEV, EPSS and CVSS data; it is not an editorial verdict.
- Yes, if you run Microsoft Office. CISA added this CVE to its Known Exploited Vulnerabilities catalog on 2026-02-10, which means there is reliable evidence of exploitation in the wild. US federal agencies must remediate by 2026-03-03; treat that as the outer limit, not the target.
- EPSS 1.6%, percentile 75: FIRST’s model estimates a 1.6% chance of exploitation activity in the next 30 days, higher than 75% of all scored CVEs (moderate). EPSS is a probability, not a verdict.
- Needs local access needed. Lower urgency for most teams unless an attacker could already run code on the machine.
What it is
Reliance on untrusted inputs in a security decision in Microsoft Office Word allows an unauthorized attacker to bypass a security feature locally.
CISA’s summary
Microsoft Office Word contains a reliance on untrusted inputs in a security decision vulnerability that could allow an authorized attacker to elevate privileges locally.
Weakness type: CWE-807.
Product: Microsoft Office · Assigned by: microsoft · Published: 2026-02-10
Affected and fixed versions
| Vendor | Product | Affected versions (per CVE record) |
|---|---|---|
| Microsoft | Microsoft 365 Apps for Enterprise | 16.0.1 < https://aka.ms/OfficeSecurityReleases |
| Microsoft | Microsoft Office LTSC 2021 | 16.0.1 < https://aka.ms/OfficeSecurityReleases |
| Microsoft | Microsoft Office LTSC 2024 | 16.0.0 < https://aka.ms/OfficeSecurityReleases |
| Microsoft | Microsoft Office LTSC for Mac 2021 | 16.0.1 < 16.106.26020821 |
| Microsoft | Microsoft Office LTSC for Mac 2024 | 16.0.0 < 16.106.26020821 |
Severity scores
| Scored by | CVSS | Score | Vector |
|---|---|---|---|
| microsoft | 3.1 | 7.8 High | CVSS:3.1/AV:L/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H/E:F/RL:O/RC:C |
- Attack vector: local access needed
- Attack complexity: low
- Privileges required: none (no login)
- User interaction: required (a user must click/open something)
- Scope: unchanged
CVSS measures how bad a flaw is if exploited, not how likely exploitation is. Read it next to the exploitation data below.
Exploitation and urgency
- CISA KEV: added 2026-02-10; federal due date 2026-03-03. Known ransomware use: Unknown.
- CISA required action: Apply mitigations per vendor instructions, follow applicable BOD 22-01 guidance for cloud services, or discontinue use of the product if mitigations are unavailable.
- CISA SSVC assessment: exploitation active, automatable no, technical impact total.
- FIRST EPSS (model of 2026-10-21): 1.59% probability of exploitation activity in the next 30 days; percentile 75.
Timeline
- — Added to CISA’s Known Exploited Vulnerabilities catalog
- — CVE record published by microsoft
- — CISA remediation deadline for US federal agencies
- — CVE record last updated
Sources and references
Original sources first. Version and fix details should always be confirmed against the vendor or project advisory.
Vendor and project advisories, patches
- Microsoft Word Security Feature Bypass Vulnerability msrc.microsoft.com
Vulnerability records
- CVE.org record CVE-2026-21514 cve.org
- NVD entry CVE-2026-21514 nvd.nist.gov
Government
All exploited Microsoft vulnerabilities · Today’s Security Digest