MSP Threat Radar Weekly Briefing — Week of 2026-06-29

This week’s briefing tracks 12 recent watch items across 2 vendors, with emphasis on active service incidents and high-priority operational issues.

Top items

Microsoft SharePoint Server Deserialization of Untrusted Data Vulnerability

• Vendor: Microsoft
• Published: 2026-07-01
• Status: active
• Source: cisa-kev
• Official advisory: https://msrc.microsoft.com/update-guide/vulnerability/CVE-2026-45659

Microsoft SharePoint Server contains a deserialization of untrusted data vulnerability which allows an authorized attacker to execute code over a network.

Apply mitigations in accordance with vendor instructions, ensuring compliance with CISA’s BOD 26-04 Prioritizing Security Updates Based on Risk (see URL in Notes) guidance and CISA’s “Forensics Triage Requirements” (see URL in Notes). Follow applicable BOD 26-04 guidance for cloud services or discontinue use of the product if mitigations are unavailable. Stakeholders are responsible for evaluating each asset's internet exposure and ensuring adherence to BOD 26-04 patching guidelines. Due date: 2026-07-04.

SimpleHelp Authentication Bypass Vulnerability

• Vendor: Simplehelp
• Published: 2026-06-29
• Status: active
• Source: cisa-kev
• Official advisory: https://simple-help.com/security/simplehelp-security-update-2026-05

SimpleHelp contains an authentication bypass vulnerability in the OIDC authentication flow. When OIDC authentication is configured, identity tokens submitted during login are accepted without verifying their cryptographic signature. In a vulnerable configuration, a remote, unauthenticated attacker can submit a forged token containing arbitrary identity claims to obtain a fully authenticated technician session. In some configurations, this may also allow bypass of multi-factor authentication.

Apply mitigations in accordance with vendor instructions, ensuring compliance with CISA’s BOD 26-04 Prioritizing Security Updates Based on Risk (see URL in Notes) guidance and CISA’s “Forensics Triage Requirements” (see URL in Notes). Follow applicable BOD 26-04 guidance for cloud services or discontinue use of the product if mitigations are unavailable. Stakeholders are responsible for evaluating each asset's internet exposure and ensuring adherence to BOD 26-04 patching guidelines. Due date: 2026-07-02.

Microsoft Edge (Chromium-based) Remote Code Execution Vulnerability (CVE-2026-58289)

• Vendor: Microsoft
• Published: 2026-07-03
• Status: active
• Source: msrc
• Official advisory: https://msrc.microsoft.com/update-guide/vulnerability/CVE-2026-58289

Information published.

Customer action is required. Review the Security Update Guide entry, confirm affected Microsoft products, and prioritize patch validation or mitigation.

Microsoft Edge (Chromium-based) Security Feature Bypass Vulnerability (CVE-2026-57983)

• Vendor: Microsoft
• Published: 2026-07-03
• Status: active
• Source: msrc
• Official advisory: https://msrc.microsoft.com/update-guide/vulnerability/CVE-2026-57983

Information published.

Customer action is required. Review the Security Update Guide entry, confirm affected Microsoft products, and prioritize patch validation or mitigation.

Microsoft Edge (Chromium-based) Spoofing Vulnerability (CVE-2026-57977)

• Vendor: Microsoft
• Published: 2026-07-03
• Status: active
• Source: msrc
• Official advisory: https://msrc.microsoft.com/update-guide/vulnerability/CVE-2026-57977

Information published.

Customer action is required. Review the Security Update Guide entry, confirm affected Microsoft products, and prioritize patch validation or mitigation.