CVE-2023-29357 — Sharepoint Server
CRITICALCVE-2023-29357 is a critical-severity (CVSS 9.8) CWE-303 vulnerability in microsoft sharepoint server. It is in CISA's Known Exploited Vulnerabilities catalog (added 2024-01-10) and has been used in ransomware campaigns — treat it as actively exploited and patch now. No vendor fix is recorded yet; mitigation options are listed below.
Microsoft SharePoint Server Elevation of Privilege Vulnerability
Exploitation Status
Actively exploited in the wild
- Confirmed by CISA's Known Exploited Vulnerabilities catalog on 2024-01-10 — including use in ransomware campaigns. Federal agencies were required to remediate by 2024-01-31.
- CISA assesses this as automatable — exploitation doesn’t require manual, per-target effort, which raises the odds of mass scanning and opportunistic attacks.
- A successful exploit gives an attacker total control of the affected component, not partial access.
Exploitation and automatability from CISA (KEV catalog and SSVC triage) for CVE-2023-29357.
EPSS Exploitation Probability
Probability of exploitation in the next 30 days, from FIRST.org EPSS.
How urgent is this, really
CVE-2023-29357 by exploitation likelihood (EPSS) against impact (CVSS). In the shaded patch-first corner (EPSS 50%+, CVSS 7.0+).
Where this sits among everything scored
Of 395,249 CVEs with a current EPSS score, this one falls in the ≥ 90% band (highlighted). Counts from FIRST.org, log-scaled.
Description
Microsoft SharePoint Server Elevation of Privilege Vulnerability
Affected Products
sharepoint servermicrosoftResearch use only. For defensive security, authorized penetration testing, and academic research only. Never execute exploit code against systems without explicit written authorization.
Microsoft SharePoint Server Elevation of Privilege Vulnerability
Microsoft SharePoint Server Elevation of Privilege Vulnerability
Microsoft SharePoint Server Elevation of Privilege Vulnerability
Microsoft SharePoint Server Elevation of Privilege Vulnerability
Microsoft SharePoint Server Elevation of Privilege Vulnerability
Detection & mitigation playbook
Vendor / applianceDetect
Inventory every microsoft sharepoint server deployment and check each version against the affected-products list above.
Remediation status
No patch has shipped for CVE-2023-29357 yet — track the microsoft sharepoint server advisory for a fixed release and apply the workarounds below in the meantime.
Mitigate without a patch
If you can't upgrade right away: gate or disable the affected feature, validate untrusted input at the boundary, and avoid passing attacker-controlled data into the vulnerable path. O3's runtime protection blocks exploitation in production as an interim safeguard until the upgrade lands. Alongside that, restrict the management interface to trusted networks and apply the vendor's recommended configuration mitigations.
How to detect CVE-2023-29357
A community-maintained Nuclei template exists for this CVE. You can scan for it directly:
nuclei -id cve-2023-29357 -u https://target- Template
- Microsoft SharePoint - Authentication Bypass
- Severity
- critical
- Impact
- Unauthenticated attackers can bypass authentication by forging JWT tokens with "none" algorithm to access SharePoint Server APIs, potentially gaining elevated privileges and accessing sensitive documents, user information, and SharePoint site configurations.
- Remediation
- Apply Microsoft security patches from MSRC update guide CVE-2023-29357 that properly validates JWT token signatures and prevents authentication bypass in SharePoint Server.
Template by ProjectDiscovery nuclei-templates (pdteam), MIT licensed. View the full template. Scan only systems you are authorised to test.
Frequently Asked Questions
Is CVE-2023-29357 being exploited in your environment?
Detect and block the exploit chain at execution, on systems you cannot patch yet.