CVE-2026-21514: Microsoft Office Word Reliance on Untrusted Inputs in a Security Decision Vulnerability

criticalknown exploitedpublic exploitCVE-2026-21514

Actively exploited. At least one CVE in this advisory is listed in the CISA Known Exploited Vulnerabilities catalog — exploitation has been observed in the wild. Treat remediation as urgent.

Microsoft Office Word contains a reliance on untrusted inputs in a security decision vulnerability that could allow an authorized attacker to elevate privileges locally.

CSIRTS triage

vendor: Microsoft product: Office Word Privilege escalation

What: A reliance on untrusted inputs in a security decision could allow an authorized attacker to elevate privileges locally.
Who is affected: Deployments of Microsoft Office Word.
Urgency: Remediation is urgent due to active exploitation and critical severity.
Action: Update Microsoft Office Word to the latest version.

AI-assisted analysis generated from the source advisory — verify against the original.

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Details

Source: CISA Known Exploited Vulnerabilities (US · database · site)
Severity: critical
Published: 2026-02-10
Exploitation: Observed in the wild (CISA KEV)

Original advisory: https://nvd.nist.gov/vuln/detail/CVE-2026-21514

Exploitation outlook

EPSS (FIRST.org) estimates each CVE’s probability of exploitation in the next 30 days — here is the CSIRTS.com read on those numbers.

Exploitation confirmedCVE-2026-21514Already exploited in the wild (CISA KEV) — the prediction phase is over. Patch now. Riskier than 73% of all EPSS-scored CVEs.

Referenced CVEs

CVE	CSIRTS overview	External
CVE-2026-21514	coverage & exploitation status	NVD · CVE.org

Recent advisories for Microsoft Office Word

A cluster of recent advisories against the same product widens the attack surface — attackers routinely chain freshly published CVEs on one product, so review these together.

mediumCVE-2026-70105: Improper input validation in Microsoft Office Word allows an unauthorized attacker to disclose…nvd · 2026-08-20
mediumCVE-2026-70319: Improper input validation in Microsoft Office Word allows an unauthorized attacker to disclose…nvd · 2026-08-11
highCVE-2026-70311: Use after free in Microsoft Office Word allows an unauthorized attacker to execute code locall…nvd · 2026-08-11
mediumCVE-2026-70310: Out-of-bounds read in Microsoft Office Word allows an unauthorized attacker to disclose inform…nvd · 2026-08-11
mediumCVE-2026-66810: Heap-based buffer overflow in Microsoft Office Word allows an unauthorized attacker to disclos…nvd · 2026-08-11
mediumCVE-2026-66806: Off-by-one error in Microsoft Office Word allows an unauthorized attacker to disclose informat…nvd · 2026-08-11

CVE-2026-21514: Microsoft Office Word Reliance on Untrusted Inputs in a Security Decision Vulnerability

CSIRTS triage

Details

Exploitation outlook

Referenced CVEs

Recent advisories for Microsoft Office Word

More from CISA Known Exploited Vulnerabilities