A flaw was identified in the RAR5 archive decompression logic of the libarchive library, specifically within the archive_read_data() processing path
Description
A flaw was identified in the RAR5 archive decompression logic of the libarchive library, specifically within the archive_read_data() processing path
Remediation
Apply vendor security updates immediately. Monitor for exploitation attempts and review access logs.
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VENDOR: Microsoft
PRODUCT: Microsoft 365 Copilot
AFFECTED_VERSIONS: See vendor advisory
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Description Summary:
An open redirect vulnerability in Microsoft 365 Copilot could be leveraged by an unauthorized attacker to facilitate privilege escalation over a network.
Executive Summary:
Microsoft 365 Copilot is affected by an open redirect vulnerability that can be chained by an attacker to successfully escalate privileges.
Vulnerability Details
CVE-ID: CVE-2026-41106
Affected Software: Microsoft 365 Copilot
Affected Versions: See vendor advisory
Vulnerability: The vulnerability is an open redirect flaw where the application fails to properly validate destination URLs. An unauthorized attacker can leverage this to redirect users to malicious sites, facilitating credential harvesting or privilege escalation.
Business Impact
With a CVSS score of 9.3, this vulnerability represents a significant risk to organizational identity and access management. Successful exploitation could allow an attacker to bypass security controls, leading to unauthorized access to enterprise data and potential full account takeover.
Remediation Plan
Immediate Action: Apply the latest security updates provided by Microsoft through the Microsoft 365 admin center or automatic update channels immediately.
Proactive Monitoring: Monitor authentication logs for unusual redirect patterns or spikes in unauthorized access attempts originating from external, untrusted sources.
Compensating Controls: Implement strict URL filtering and enforce secure authentication protocols, such as phishing-resistant Multi-Factor Authentication (MFA), to limit the impact of potential redirect-based attacks.
Exploitation Status
Public Exploit Available: N/A
Analyst Notes: As of Jul 2, 2026, there is no public information indicating active exploitation of this vulnerability. However, the potential for exploitation in enterprise environments is high given the target application.
Analyst Recommendation
The severity of this vulnerability necessitates immediate patching. Security teams should verify that all instances of Microsoft 365 Copilot are updated to the latest version to prevent potential privilege escalation and unauthorized access to sensitive corporate resources.