---
id: "CVE-2023-29357"
kind: "vulnerability"
aliases: ["CVE-2023-29357"]
title: "Microsoft SharePoint Server Elevation of Privilege Vulnerability"
severity: "critical"
cvss: 9.8
epss: null
exploited: true
status: "open"
category: "infrastructure"
products: [{"name": "Microsoft SharePoint Server", "fixed": [], "affected": "", "ecosystem": "vendor"}, {"name": "microsoft sharepoint server", "fixed": [], "affected": "= 2019", "ecosystem": "vendor"}]
ecosystems: ["vendor"]
tags: ["exploited", "infrastructure", "ransomware", "self-hosted", "sharepoint-server", "windows"]
not_affected_if: ["managed-hosting", "sharepoint-online"]
published_at: "2023-06-14T00:15:09+00:00"
first_seen_at: "2026-10-23T19:11:51+00:00"
updated_at: "2026-10-23T22:29:05+00:00"
sources: [{"source": "kev", "url": "https://www.cisa.gov/known-exploited-vulnerabilities-catalog?search_api_fulltext=CVE-2023-29357", "first_seen_at": "2026-10-23T19:11:51+00:00"}, {"source": "nvd", "url": "https://nvd.nist.gov/vuln/detail/CVE-2023-29357", "first_seen_at": "2026-10-23T22:29:05+00:00"}]
---

# Microsoft SharePoint Server Elevation of Privilege Vulnerability

Microsoft SharePoint Server accepts spoofed JWT authentication tokens, so a network attacker can bypass authentication. The attacker gets administrator privileges on the server.

_Summary, check and fix written by a model from the sources; labelled as such._

## Affected

- vendor:Microsoft SharePoint Server affected ? fixed ?
- vendor:microsoft sharepoint server affected = 2019 fixed ?

## Fix

Apply the Microsoft mitigations for CVE-2023-29357 per vendor instructions, or stop using the affected SharePoint Server if mitigations are unavailable (CISA required action).

## Timeline

- 2026-10-23T19:11:51+00:00 kev https://www.cisa.gov/known-exploited-vulnerabilities-catalog?search_api_fulltext=CVE-2023-29357
- 2026-10-23T22:29:05+00:00 nvd https://nvd.nist.gov/vuln/detail/CVE-2023-29357

## From the sources

Microsoft SharePoint Server contains an unspecified vulnerability that allows an unauthenticated attacker, who has gained access to spoofed JWT authentication tokens, to use them for executing a network attack. This attack bypasses authentication, enabling the attacker to gain administrator privileges.

CISA required action: Apply mitigations per vendor instructions or discontinue use of the product if mitigations are unavailable.

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_Free to read at a human pace. An API with keys and an MCP server are in preparation; early access: hello@infrastack.ai_