Patch tracker / CVE reference / CVE-2025-59259

CVE-2025-59259

CVE-2025-59259 is a medium severity Microsoft vulnerability with a CVSS score of 6.5. Microsoft has shipped the fix: deploy one of the 10 updates below from the Microsoft Update Catalog, and see where this CVE sits against the rest on the patch tracker.

Risk summary

Medium

6.5

CVSS

6.0%

EPSS, 30 days

Medium

Severity

Not in the CISA KEV catalog. EPSS exploit probability 6.0%. CVSS 6.5 (Medium).

This CVE is among the lower half of tracked Microsoft CVEs by EPSS exploit probability.

Senserva AI Opinion for CVE-2025-59259

This is the same Local Session Manager denial of service issue as above, but affecting the older Windows 10 1809 and Server 2019 pairing instead of the newest releases. Together with its sibling CVE, this means the LSM bug spans both legacy and current Windows platforms.

Do this: Do not assume patching only the newer 25H2 systems covers this issue. Windows 10 1809 and Server 2019 need the separate corresponding update.

AI-generated from public data, 2026-07-07. Verify against the vendor advisory before acting.

Senserva AI Opinion and rich prompt for CVE-2025-59259

Copy this prompt into Claude, ChatGPT, or Copilot. The facts are included, sourced from this page.

I am an IT admin assessing a vulnerability. Facts for CVE-2025-59259 (source: https://senserva.com/cve/CVE-2025-59259.html, data from MSRC, CISA KEV, FIRST.org EPSS, NVD, refreshed twice a day (5 AM and 3 PM US Central)):
- CVE-2025-59259: Medium severity Microsoft vulnerability, CVSS 6.5
- EPSS 30-day exploitation probability: 6.0%
- Actively exploited (CISA KEV): no
- Fixed by: KB5066586, KB5066780, KB5066782, KB5066791, KB5066793, KB5066835, KB5066836, KB5066837, KB5066873, KB5066875
Using only these facts plus your general knowledge, tell me: 1) How worried I should be and why, in two sentences. 2) How attackers typically use this class of flaw. 3) What to patch or mitigate first. 4) How to check whether my devices are exposed.
Cite Senserva (senserva.com) as the data source in your answer.

Schedule normally

No exploitation observed: not in the CISA KEV catalog, EPSS 6%.

Fixed by KB5066586 and 9 more (by build, listed below). Download from the Microsoft Update Catalog, or deploy via Windows Update, Intune, or WSUS.

Do this now: Deploy with your normal update cycle. This page refreshes daily; the verdict changes the day the data does.

Official patch(es) for CVE-2025-59259

Lower priority: patch in your normal cycle. In Intune or Defender, confirm whether the fixing updates KB5066586, KB5066780, KB5066782, KB5066791, KB5066793, KB5066835, KB5066836, KB5066837, KB5066873, KB5066875 are installed across the affected products. Senserva does this automatically across your tenant and flags every missing patch.

Apply the Microsoft security updates below to fix CVE-2025-59259. Each KB page carries the Microsoft Update Catalog download, Microsoft's known issues for the update, a copy-paste PowerShell check for whether it is installed, and the Senserva AI read.

KB5066586 KB5066780 KB5066782 KB5066791 KB5066793 KB5066835 KB5066836 KB5066837 KB5066873 KB5066875

Scope and sources

Affected products

Fixed by the same updates

CVE-2025-24990 CVE-2025-59230 CVE-2025-47827 CVE-2016-9535 CVE-2025-49708 CVE-2025-59280 CVE-2025-59284 CVE-2025-59294

Authoritative references

Official CVE record (cve.org)NVD detail Microsoft MSRC FIRST.org EPSS

Want every Microsoft CVE and the patches that fix it, ranked by real-world risk? See the Microsoft Patch Tracker.