Patch tracker / KB5002858

KB5002858: Microsoft Office 2019 for 32-bit editi Security Update (May 2026)

KB5002858 is a High security update for Microsoft Office 2019 for 32-bit editi, released 2026-05-12. It closes 6 CVEs with a maximum CVSS of 8.4. The most likely of them to be attacked is CVE-2026-40367, which FIRST.org rates at 9% probability of exploitation in the next 30 days.

Update summary

High
2026-05-12
Released
6
CVEs fixed
8.4
Max CVSS
High
Severity
Deploy this cycle
Fixes 6 CVEs for Microsoft Office 2019 for 32-bit editi. No confirmed in-the-wild exploitation in this set today.

Fixes 6 CVEs. Most severe CVSS 8.4 (High). EPSS exploit probability up to 4.4%. Among the top half of tracked Microsoft updates by EPSS exploit probability.

Senserva found thiswe track every release for this product line, so we can tell you this package is behind

A newer security update for Microsoft Office 2019 for 32-bit editions has shipped since this one: KB5002273 (2026-07-14). For cumulative update families the newer package includes these fixes, so installing that one is usually the shorter path. Verify against your own update rings before you skip this package.

Senserva found thisno known issues as of our last check

We checked Microsoft's support article for KB5002858 on 2026-08-06 and it lists no known issues. Read the article before broad deployment; Microsoft adds issues as reports come in, and we re-check on every refresh.

Microsoft Update Catalog: download KB5002858Microsoft support article
Senserva AI Opinion for KB5002858

KB5002858 patches 6 CVEs in Office 2019 and Microsoft 365 Apps, with a top rating of High (CVSS 8.4). Anyone running these Office builds on 32-bit or 64-bit Windows is exposed, which in practice means most desktop fleets. None of these CVEs are in CISA KEV or ransomware-linked, and the highest EPSS is 4%, so this is a patch-on-schedule case rather than an emergency drop.

Do this: Push KB5002858 to your Office 2019 and Microsoft 365 Apps clients through your normal patch ring this cycle.

AI-generated from public data, 2026-07-21. Verify against the vendor advisory before acting.

Senserva AI Opinion and rich prompt for KB5002858

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

Full tracking and change history for KB5002858

Released
2026-05-12
Last changed
2026-05-12
Changes tracked
1

Senserva began recording day-to-day change history on 2026-07-07, and refreshes it several times a day. Release dates are historical where Microsoft publishes them; revision history is tracked from that date forward, so it does not include changes made before then.

Check if KB5002858 is installed

Elevated PowerShell. No output means it is not installed.

CVEs fixed by this update

Sorted exploited-first, then by CVSS. Every CVE links to its Senserva page with the full risk facts, references, and a ready-to-paste AI prompt.

CVESeverityCVSSEPSSExploited
CVE-2026-40367High8.89.1%No
CVE-2026-35440High8.44.4%No
CVE-2026-40361High8.44.4%No
CVE-2026-40364High8.44.4%No
CVE-2026-40366High8.44.4%No
CVE-2026-40421High8.44.4%No

Scope and sources

Affected products
Also released in May 2026

KB5002863

9 CVEs · High · exploited

KB5002868

9 CVEs · High · exploited

KB5002870

9 CVEs · High · exploited

KB5078943

3 CVEs · Critical

KB5087420

56 CVEs · Critical

KB5087424

56 CVEs · Critical

KB5087470

39 CVEs · Critical

KB5087471

42 CVEs · Critical

The full month, summarized: Microsoft Patch Tuesday.

Authoritative references
Official KB5002858 page (Microsoft Support)Microsoft Update CatalogMicrosoft Security Update Guide

See this and every Microsoft update ranked by real-world risk on the Microsoft Patch Tracker.

New to a term on this page? CVE, KB, KEV, CVSS, and EPSS are each explained once, on the Senserva security lexicon. Reference: Microsoft CVE and vulnerability management and the Microsoft patching guide.
Provided as is, without warranty; verify against the vendor advisory before acting. Data notice and terms.