October 2025 Patch TuesdayKB5066366Normal patch window

Microsoft · KB5066366

Linked CVE review

Deploy Microsoft Server Software security update KB5066366

Linked CVEs
3
Confirmed exploited
0
PoC or lab evidence
0
Maximum CVSS
8.8
Evidence is kept separate

Confirmed exploitation, public exploit material, EPSS probability and CVSS severity answer different questions. “No confirmation recorded” means the checked sources do not currently confirm exploitation. It is not proof that exploitation has not occurred.

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3 of 3 linked CVEs shown
Confirmed exploitedCVSS above 9.0
CVE and descriptionSeverityExploit realityForecast and accessRemediation
CVE-2025-59248 Scheduled assessment
Microsoft Exchange Server Spoofing Vulnerability

Improper input validation in Microsoft Exchange Server allows an unauthorized attacker to perform spoofing over a network.

7.5 · CVSS 3.1 · HighSource: CNANo confirmation recordedNo CISA KEV match was present at the last successful refresh. This means no confirmation from that source, not proof of no exploitation.None recordedNo exploit-tagged reference or CISA SSVC proof-of-concept state is currently recorded. Research may still exist outside the structured feeds.EPSS: 1.02% · 62.2th percentileForecast date: 2026-10-06NETWORK · LOW complexity · NONE privileges · NONE user interactionWithin 7 daysHigh technical severity; prioritise exposed affected systems while verifying vendor guidance.Awaiting fix. No fixed version is explicitly recorded in the structured CVE data.
CVE-2025-59249 Scheduled assessment
Microsoft Exchange Server Elevation of Privilege Vulnerability

Weak authentication in Microsoft Exchange Server allows an authorized attacker to elevate privileges over a network.

8.8 · CVSS 3.1 · HighSource: CNANo confirmation recordedNo CISA KEV match was present at the last successful refresh. This means no confirmation from that source, not proof of no exploitation.None recordedNo exploit-tagged reference or CISA SSVC proof-of-concept state is currently recorded. Research may still exist outside the structured feeds.EPSS: 0.83% · 56.1th percentileForecast date: 2026-10-06NETWORK · LOW complexity · LOW privileges · NONE user interactionWithin 7 daysHigh technical severity; prioritise exposed affected systems while verifying vendor guidance.Awaiting fix. No fixed version is explicitly recorded in the structured CVE data.
CVE-2025-53782 Scheduled assessment
Microsoft Exchange Server Elevation of Privilege Vulnerability

Incorrect implementation of authentication algorithm in Microsoft Exchange Server allows an unauthorized attacker to elevate privileges locally.

8.4 · CVSS 3.1 · HighSource: CNANo confirmation recordedNo CISA KEV match was present at the last successful refresh. This means no confirmation from that source, not proof of no exploitation.None recordedNo exploit-tagged reference or CISA SSVC proof-of-concept state is currently recorded. Research may still exist outside the structured feeds.EPSS: 0.36% · 27.2th percentileForecast date: 2026-10-06LOCAL · LOW complexity · NONE privileges · NONE user interactionWithin 7 daysHigh technical severity; prioritise exposed affected systems while verifying vendor guidance.Awaiting fix. No fixed version is explicitly recorded in the structured CVE data.