Microsoft SharePoint Deserialization of Untrusted Data Vulnerability

Microsoft SharePoint

Microsoft SharePoint contains a deserialization of untrusted data vulnerability that allows an unauthorized attacker to execute code over a network. Added to CISA KEV on 2026-03-18 (federal deadline 2026-03-21).

First seen: 18 Mar 2026
Last update: 18 Mar 2026, 12:00 UTC
Identifiers: CVE-2026-20963
Source: CISA KEV
On the menu as: Microsoft Office

Check this repository for exposure to one security incident from pwned.coffee. Report first, change nothing until I say so.

## Microsoft SharePoint Deserialization of Untrusted Data Vulnerability
Severity: high, exploited in the wild. Patch status: patched.
Affected: Microsoft SharePoint
Ids: CVE-2026-20963

Microsoft SharePoint contains a deserialization of untrusted data vulnerability that allows an unauthorized attacker to execute code over a network. Added to CISA KEV on 2026-03-18 (federal deadline 2026-03-21).

## Steps
1. This touches infrastructure (office). Look in terraform, ansible, cloud-init, Dockerfiles and docs for the product and version we run. If it isn't in the repo, say so and list what a human should check on the box.

## Report
A table: file, product or package, version in use, affected yes/no, exact fix. Then anything a human has to check outside the repo.

If you have the pwned.coffee MCP server (https://pwned.coffee/mcp), call lookup_cve("CVE-2026-20963") for the latest, and check_repo with this repo's lockfiles, Dockerfiles and workflows for a full receipt.
Sources: https://msrc.microsoft.com/update-guide/vulnerability/CVE-2026-20963 https://nvd.nist.gov/vuln/detail/CVE-2026-20963
https://pwned.coffee/i/microsoft-sharepoint-deserialization-of-untrusted-data-v-cve-2026-20963

Sources

Totalone hot coffee