CVE-2026-45455: Microsoft Excel Information Disclosure Vulnerability

lowCVSS 3.3CVE-2026-45455

Out-of-bounds read in Microsoft Office Excel allows an unauthorized attacker to disclose information over a network.

CSIRTS triage

vendor: Microsoft product: Microsoft Excel Information disclosure

What: Out-of-bounds read in Microsoft Office Excel allows an unauthorized attacker to disclose information over a network.
Who is affected: Unauthorized attackers can exploit this vulnerability if they can access the network.
Urgency: Remediation is low urgency due to the lower severity of information disclosure.
Action: Apply the latest security updates from Microsoft.

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

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Details

Source: Microsoft Security Response Center (INTL · vendor-psirt · site)
Severity: low — CVSS 3.3
Published: 2026-06-09
Exploitation: Not in CISA KEV at last sync

Original advisory: https://msrc.microsoft.com/update-guide/vulnerability/CVE-2026-45455

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.

Low exploitation riskCVE-2026-454550.63% 30-day exploitation probability — currently an unlikely target, but scores change as exploit code circulates. Riskier than 46% of all scored CVEs.

Referenced CVEs

CVE	CSIRTS overview	External
CVE-2026-45455	coverage & exploitation status	NVD · CVE.org

Recent advisories for Microsoft Excel Information

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.

highCVE-2026-44822: Microsoft Excel Information Disclosure Vulnerabilitymsrc · 2026-06-09