CVE-2026-70329: Microsoft Outlook Remote Code Execution Vulnerability
Integer overflow or wraparound in Microsoft Office Outlook allows an unauthorized attacker to execute code over a network.
CSIRTS triage
- What
- Integer overflow in Outlook allows unauthorized remote code execution over the network.
- Who is affected
- Outlook users receiving malicious messages or attachments.
- Urgency
- High priority; CVSS 8.8 with unauthenticated RCE over network requires immediate remediation.
- Action
- Apply Microsoft security updates for Outlook immediately.
AI-assisted analysis generated from the source advisory — verify against the original.
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Details
Original advisory: https://msrc.microsoft.com/update-guide/vulnerability/CVE-2026-70329
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-2026-703290.64% 30-day exploitation probability — currently an unlikely target, but scores change as exploit code circulates. Riskier than 48% of all EPSS-scored CVEs.
Referenced CVEs
| CVE | CSIRTS overview | External |
|---|---|---|
| CVE-2026-70329 | coverage & exploitation status | NVD · CVE.org |
Same CVEs, other sources
How other CERTs, PSIRTs and databases cover the vulnerabilities in this advisory.
Recent advisories for Microsoft Outlook Remote
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-2026-45458: Microsoft Outlook and Word Remote Code Execution Vulnerabilitymsrc · 2026-06-09
- highCVE-2026-45456: Microsoft Outlook and Word Remote Code Execution Vulnerabilitymsrc · 2026-06-09
- highCVE-2026-47635: Microsoft Outlook and Word Remote Code Execution Vulnerabilitymsrc · 2026-06-09
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