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Superseded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 2027

Wed 1 Dec

Thu 2 Dec

Fri 3 Dec

Sat 4 Dec

Sun 5 Dec

Mon 6 Dec

Tue 7 Dec

Wed 8 Dec

Thu 9 Dec

Fri 10 Dec

Sat 11 Dec

Sun 12 Dec

Mon 13 Dec

Tue 14 Dec

Patch Tuesday

Wed 15 Dec

Thu 16 Dec

Fri 17 Dec

Sat 18 Dec

Sun 19 Dec

Mon 20 Dec

Tue 21 Dec

Wed 22 Dec

Thu 23 Dec

Fri 24 Dec

Sat 25 Dec

Sun 26 Dec

Mon 27 Dec

Tue 28 Dec

Wed 29 Dec

Thu 30 Dec

Fri 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