SharePoint Server: Server-side request forgery allows privilege elevation
Summary
A server-side request forgery (CWE-918) in on-premises Microsoft SharePoint Server Subscription Edition allows an authorized attacker to elevate privileges over the network. The attacker needs a valid low-privileged SharePoint account and specific conditions apply (AC:H). Microsoft rates the issue Important with a CVSS 3.1 base score of 7.5. It is not known to be exploited in the wild.
Affected
- Microsoft SharePoint Server Subscription Edition (x64) before build 16.0.20326.20190
- SharePoint Server 2016 and 2019: unverified, check the MSRC page and KB5002927 before assuming coverage
Fixed in
Build 16.0.20326.20190 or later, shipped with security update KB5002927 (October 13, 2026). Prerequisite: the release version of Subscription Edition must already be installed.
Workaround
Unknown. No vendor-published workaround was found. Applying the patch removes the need for one.
Exploitation
- Not known to be exploited in the wild; not listed in the CISA KEV catalogue.
- CISA SSVC: exploitation none, automatable no, technical impact total.
- Microsoft temporal vector uses E:U (exploit code maturity unproven).
- No public proof of concept found (this does not rule one out).
- EPSS about 0.6%.
Our recommendation
- Patch to build 16.0.20326.20190 or later with KB5002927 on every farm server and confirm the build afterwards.
- Check whether SharePoint is published to the internet or reachable from partner or guest networks, and restrict access if so.
- Review accounts with SharePoint access, especially external and guest accounts, and remove unneeded ones.
- Monitor SharePoint logs for unusual outbound requests and privilege changes.
- Organisations using only SharePoint Online in Microsoft 365 are not covered by this on-premises patch.
Information from Microsoft (Patch Tuesday October 2026)
- Severity (Microsoft)
- Important
- Impact
- Elevation of privilege – Microsoft Office SharePoint
- Status on Patch Tuesday
- Neither exploited nor publicly disclosed
- Exploitability assessment
- Exploitation unlikely
- Product family
- Microsoft Office
- Updates (KB)
- KB5002927
Public exploits
PoC-in-GitHub, Metasploit and Exploit-DB list nothing for this CVE.
Research sources
- Microsoft Security Update Guide: CVE-2026-70251 msrc.microsoft.com
- Microsoft KB5002927 SharePoint hotfix support.microsoft.com
- OpenCVE: CVE-2026-70251 app.opencve.io
- Vulners CVE list entry: CVE-2026-70251 vulners.com
- Vulners NVD entry: CVE-2026-70251 vulners.com
Researched and written up in English and German by an AI (Claude by Anthropic) based on NVD, CISA, EPSS and the sources listed. The vendor information is authoritative. Researched on 2 Nov 2026, 18:56.
Original description (NVD)
Server-side request forgery (ssrf) in Microsoft Office SharePoint allows an authorized attacker to elevate privileges over a network.
NVD references (1)
Sources
The tracker combines official, freely usable data sources – updated continuously:
- NVD (NIST) – CVEs, rating (CVSS), affected products
- CISA KEV – vulnerabilities confirmed by CISA as actively exploited
- CISA Vulnrichment – CISA assessment (SSVC) in the official CVE record
- FIRST EPSS – probability of exploitation
- Microsoft MSRC – Patch Tuesday: vulnerabilities, severity, updates
- PoC-in-GitHub – public proof-of-concept repositories
- Metasploit (Rapid7) – modules of the Metasploit Framework
- Exploit-DB (OffSec) – archive of public exploits (links only)
- Patch days: official vendor pages (linked per vendor) (Vendor patch days)
This product uses data from the NVD API but is not endorsed or certified by the NVD. EPSS data © FIRST.org.
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