Tuesday 9 December 2025

December 2025: is it safe to deploy?

What Microsoft fixed, how urgent it is, and whether anything broke, per Windows version, from Microsoft's release tables, release health, MSRC, CISA, and what the community reports.

← Nov 2025 Jan 2026 →

Superseded

Newer updates replace December 2025.

The CVEs it fixes are unknown; no open known issues found in the current public evidence; out-of-band fixes followed on 18 Dec. See November 2026 Patch Tuesday.

MSRC's December 2025 security update document isn't collected.

ChangeIntel's reading of public signals, not advice; check Microsoft's guidance and test before you deploy. Terms

Microsoft CVEs: Unknown
Exploited fixed: Unknown
In CISA KEV: Unknown
Open known issues: 0
Out-of-band: 3

Release calendar · December 2025

Mon 1 Dec

KB5070311 · Win 11 24H2, Win 11 25H2

Tue 2 Dec

Wed 3 Dec

Thu 4 Dec

Fri 5 Dec

Sat 6 Dec

Sun 7 Dec

Mon 8 Dec

Tue 9 Dec

Wed 10 Dec

Thu 11 Dec

Fri 12 Dec

Sat 13 Dec

Sun 14 Dec

Mon 15 Dec

Tue 16 Dec

Wed 17 Dec

Thu 18 Dec

Fri 19 Dec

Sat 20 Dec

Sun 21 Dec

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Tue 23 Dec

Wed 24 Dec

Thu 25 Dec

Fri 26 Dec

Sat 27 Dec

Sun 28 Dec

Mon 29 Dec

Tue 30 Dec

Wed 31 Dec

Patch Tuesday and security (B) releasesPreview (D) releasesOut-of-band releases.NET Framework servicing packagesEdge, Office, Teams, Defender and server releasesAll product versions