Cyber Resilience

CVE-2023-29357

Auth Bypass in Microsoft Sharepoint Server 2019

CISA KEVActive ExploitationEUVD ExploitedRansomware-linkedAuth Bypass
Published
14 June 2023
Modified
28 October 2025
KEV Added
10 January 2024
Patch / advisory
CVSS Score v3.1 9.8
Click a component to see what it means
Raw vectorCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
EPSS Score 0.99 99.9th percentile
Risk Priority 97 floored blend · peak EPSS

Summary

CVE-2023-29357 is a critical-severity Incorrect Implementation of Authentication Algorithm (CWE-303) vulnerability in Microsoft Sharepoint Server. Its CVSS base score is 9.8 (Critical).

Operationally, exploitation aligns with the MITRE ATT&CK technique External Remote Services (T1133); ranked in the top 0.1% of CVEs by exploit likelihood; CISA has added it to the Known Exploited Vulnerabilities catalog.

Deeper analysis AI-assisted summary

Synthesised by an AI model from the NVD description and linked references — a reading aid, not an authoritative source.

Microsoft SharePoint Server is affected by an elevation of privilege vulnerability, CVE-2023-29357, that carries a CVSS 3.1 score of 9.8. The flaw permits unauthenticated network attackers to obtain full read, write, and execute rights on the server without any user interaction.

Remote, unauthenticated attackers can leverage the weakness to gain administrative control over SharePoint deployments, allowing them to access or modify sensitive content, alter configurations, or disrupt service availability.

Microsoft has issued remediation guidance through its Security Response Center, and the vulnerability is listed in CISA’s catalog of known exploited vulnerabilities, confirming active use in the wild.

The EPSS score of 0.9436 reflects consistently elevated exploitation likelihood since the June 2023 disclosure.

OWASP Top 10 for Web (2025)

EU & UK References

Vulnerability Data

Microsoft SharePoint Server Elevation of Privilege Vulnerability

CWE(s)
KEV Date Added
10 January 2024

Related Threats

MITRE ATT&CK Enterprise Techniques

T1133 External Remote Services Persistence
Adversaries may leverage external-facing remote services to initially access and/or persist within a network.
T1190 Exploit Public-Facing Application Initial Access
Adversaries may attempt to exploit a weakness in an Internet-facing host or system to initially access a network.
Derived from this CVE’s CWE(s) via the direct CWE→ATT&CK cross-walk.

CVEs Like This One

CVE-2024-38094Same product: Microsoft Sharepoint Serverboth on KEV
CVE-2023-21743Same product: Microsoft Sharepoint Server
CVE-2024-32987Same product: Microsoft Sharepoint Server
CVE-2024-49062Same product: Microsoft Sharepoint Server
CVE-2024-38018Same product: Microsoft Sharepoint Server
CVE-2024-49064Same product: Microsoft Sharepoint Server
CVE-2024-49070Same product: Microsoft Sharepoint Server
CVE-2024-43466Same product: Microsoft Sharepoint Server
CVE-2024-21318Same product: Microsoft Sharepoint Server
CVE-2024-43464Same product: Microsoft Sharepoint Server

Affected Assets

microsoft
sharepoint server
2019

Mitigating Controls

Mitigating Controls (NIST CSF 2.0) AI

Derived directly from the weakness types (CWEs) cited in the NVD entry via our AI-authored CWE→CSF cross-walk (authority under review) — links open the control.

PR.PS-06 mostly match
prevents

Secure SDLC practices directly require correct implementation of authentication algorithms.

Mitigating Controls (ISO/IEC 27001:2022 Annex A) AI

Derived directly from the weakness types (CWEs) cited in the NVD entry via our AI-authored CWE→ISO cross-walk (authority under review) — links open the control.

degrades

Secure authentication control directly requires correct implementation of authentication algorithms.

finds

Security testing can detect flawed authentication implementations but does not prevent them by itself.

degrades

Cryptography control addresses proper use of authentication algorithms but is broader than authentication alone.

prevents

Secure development lifecycle includes verification steps that can catch incorrect authentication implementations.

prevents

Application security requirements can specify correct authentication algorithm use but do not guarantee correct implementation.

prevents

Secure coding practices reduce the likelihood of incorrect authentication algorithm implementation.

References