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

This week’s briefing tracks 12 recent watch items across 8 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.

attr < 2.6.0 Symlink Traversal Privilege Escalation via getfattr/setfattr (CVE-2026-54371)

• Vendor: Microsoft
• Published: 2026-06-30
• Status: active
• Source: msrc
• Official advisory: https://msrc.microsoft.com/update-guide/vulnerability/CVE-2026-54371

Information published. Information published. Information published.

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

Cloudflare is investigating issues with network performance in ENAM and WNAM, US

• Vendor: Cloudflare
• Published: 2026-07-02
• Status: monitoring
• Source: cloudflare-status
• Official advisory: https://stspg.io/wknf2sjp9xrr

Cloudflare is investigating issues with network performance in ENAM and WNAM, US. We are working to analyse and mitigate this problem. More updates to follow shortly.

Check cloudflare dependent workflows, notify affected clients if service disruption persists, and review workaround guidance from the official incident page.

Cisco Unified Communications Manager Server-Side Request Forgery Vulnerability

• Vendor: Cisco
• Published: 2026-07-01
• Status: watch
• Source: cisco
• Official advisory: https://sec.cloudapps.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-cucm-ssrf-cXPnHcW

A vulnerability in Cisco Unified Communications Manager (Unified CM) and Cisco Unified Communications Manager Session Management Edition (Unified CM SME) could allow an unauthenticated, remote attacker to conduct server-side request forgery (SSRF) attacks through an affected device. This vulnerability is due to improper input validation for specific HTTP requests. An attacker could exploit this vulnerability by sending a crafted HTTP request to an affected device. A successful exploit could allow the attacker to write files to the underlying operating system that could be used later to elevate to root. Note: Cisco has assigned this security advisory a Security Impact Rating (SIR) of Critical rather than High as the score indicates. The reason is that exploitation of this vulnerability could result in an attacker elevating privileges to root. Note: To exploit this vulnerability, the WebDialer service must be enabled. WebDialer is disabled by default. Cisco has released software updates that address this vulnerability. There are no workarounds that address this vulnerability. This advisory is available at the following link:https://sec.cloudapps.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-cucm-ssrf-cXPnHcW <br/>Security Impact Rating: Critical <br/>CVE: CVE-2026-20230

Review the official advisory, map affected products against managed client environments, and determine whether patching or temporary mitigation is required.