Security 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 0.99 100.0th percentile
Risk Priority 97 floored blend · peak EPSS

CVSS and EPSS are reproduced from their sources (NVD, FIRST EPSS). Risk Priority is our own derived reading, not an NVD score.

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 Data Obfuscation (T1001); ranked in the top 0.0% 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

T1001 Data Obfuscation Command And Control
Adversaries may obfuscate command and control traffic to make it more difficult to detect.
T1001.003 Protocol or Service Impersonation Command And Control
Adversaries may impersonate legitimate protocols or web service traffic to disguise command and control activity and thwart analysis efforts.
T1003.005 Cached Domain Credentials Credential Access
Adversaries may attempt to access cached domain credentials used to allow authentication to occur in the event a domain controller is unavailable.
T1003.006 DCSync Credential Access
Adversaries may attempt to access credentials and other sensitive information by abusing a Windows Domain Controller's application programming interface (API)(Citation: Microsoft DRSR Dec 2017) (Citation: Microsoft GetNCCChanges) (Citati…
T1003.008 /etc/passwd and /etc/shadow Credential Access
Adversaries may attempt to dump the contents of <code>/etc/passwd</code> and <code>/etc/shadow</code> to enable offline password cracking.
T1007 System Service Discovery Discovery
Adversaries may try to gather information about registered local system services.
Derived from this CVE’s CWE(s) via the direct CWE→ATT&CK cross-walk.

CVEs Like This One

CVE-2023-21743Same product: Microsoft Sharepoint Server
CVE-2024-38094Same product: Microsoft Sharepoint Serverboth on KEV
CVE-2023-36764Same product: Microsoft Sharepoint Server
CVE-2023-36892Same product: Microsoft Sharepoint Server
CVE-2023-36891Same product: Microsoft Sharepoint Server
CVE-2024-21426Same product: Microsoft Sharepoint Server
CVE-2024-26251Same product: Microsoft Sharepoint Server
CVE-2023-33159Same product: Microsoft Sharepoint Server
CVE-2023-33130Same product: Microsoft Sharepoint Server
CVE-2023-33132Same 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 partial match
blocks

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

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

blocks

A.8.25 mandates security requirements, secure coding, checkpoints, testing and developer capability in the SDLC which reaches incorrect algorithm implementation for auth (via secure coding, testing and vuln prevention/fixing), but this is only a minority slice of the weakness class as most instances arise from flawed design/requirements rather than implementation errors caught in dev.

blocks

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.

finds

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

References