Microsoft Streaming Service Proxy Privilege Escalation Vulnerability

What it is

Microsoft Streaming Service Proxy contains an unspecified vulnerability that allows for privilege escalation.

Who's affected

Affects anyone running Microsoft Streaming Service Proxy. Microsoft products in a small practice typically sit close to credentials, email, or document workflows — treat the patch as in-scope.

What to do

Apply mitigations per vendor instructions or discontinue use of the product if mitigations are unavailable.

If you don't have someone in-house to verify the patch deployed across every endpoint — or you're not sure whether you're affected — that's exactly the kind of triage we do. Book a free 20-minute triage call.

Microsoft fix

• KB5030214 (Security Update)
• KB5030216 (Security Update)
• KB5030325 (AzureHotpatch)
• KB5030217 (Security Update)
• KB5030211 (Security Update)
• KB5030219 (Security Update)

Sourced from Microsoft Security Update Guide (CVRF document 2023-Sep).

CISA due date

Federal deadline: October 3, 2023. Federal agencies must complete the required action by this date. For private SMBs the deadline is advisory — but treat it as a strong recommendation, especially if you handle regulated data (HIPAA, GLBA, ABA model rules).

EPSS

EPSS score: 26.1% — higher than 98% of all scored CVEs.

EPSS estimates the probability of exploitation activity in the next 30 days. Every entry on this site is already confirmed exploited, so read it as relative urgency among the things you still have open, not as permission to wait.

Score dated 2026-08-12, from the FIRST.org Exploit Prediction Scoring System.

Browse more

• All Microsoft KEV entries
• All SMB-relevant KEV entries

Source

This entry comes from CISA's Known Exploited Vulnerabilities catalog, public US-Government data we pull daily. The plain-language framing and the what-to-do guidance above are ours. View the original entry on cisa.gov.