A newly disclosed Microsoft Outlook vulnerability, tracked as CVE-2025-62562, could allow for remote code execution (RCE). Read this Cybersecurity Threat Advisory to mitigate you and your clients’ risk now.
What is the threat?
This use-after-free vulnerability introduces a use-after-free flaw that allows RCE when triggered through local user interaction. With a CVSS score of 7.8, Microsoft has released security updates via Windows Update and the Download Center for affected Office and SharePoint builds. Prompt patching is strongly recommended to reduce exposure.
Why is it noteworthy?
Although there is no evidence of active exploitation, the required user action for this flaw—replying to an email—is common in daily workflows. This makes social engineering a practical attack vector. If successful, attackers could deploy malware, steal sensitive data, and move laterally within the network. Organizations with inadequate phishing awareness training face an even higher risk.
What is the exposure or risk?
Exploiting this flaw enables attackers to execute arbitrary code under the user’s context, leading to:
- Malware installation
- Data theft and credential compromise
- Abuse of privileges
- Potential lateral movement across the network
What are the recommendations?
Barracuda strongly recommends the following actions to mitigate risk:
- Use Windows Update or the Download Center to install the December 9, 2025, security patches across all affected Office/SharePoint builds. For Word 2016, confirm KB5002806 (build 16.0.5530.1000) is applied. Monitor pending fixes for Office LTSC for Mac 2021/2024.
- Deploy email gateways or advanced threat protection (e.g., Microsoft Defender for Office 365) to block suspicious or malformed emails.
- Implement stricter controls for shared or external attachments.
- Use EDR or antivirus solutions with behavior-based detection to identify post-exploit activity.
- Reinforce phishing awareness, emphasizing that replying to unexpected emails can trigger exploitation. Note: The Preview Pane is not an attack vector here.
- Include steps for isolating affected hosts, preserving malicious emails and logs, patching systems, reviewing telemetry, and rotating credentials.
References
For more in-depth information about the recommendations, please visit the following links:
- https://www.tenable.com/cve/CVE-2025-62562
- https://cybersecuritynews.com/microsoft-outlook-vulnerability/
- https://msrc.microsoft.com/update-guide/vulnerability/CVE-2025-62562
If you have any questions about this Cybersecurity Threat Advisory, don’t hesitate to get in touch with Barracuda Managed XDR’s Security Operations Center.
This post originally appeared on Smarter MSP.