Microsoft SharePoint Has a New RCE Flaw. If You Haven’t Patched Yet, Go Do That.
A critical remote code execution (RCE) vulnerability, tracked as CVE-2026-45659, affects Microsoft SharePoint Server versions including Subscription Edition, 2019, and Enterprise Server 2016. The flaw arises from deserialization of untrusted data, allowing an authenticated attacker with low privileges (Site Member) to execute code remotely over the network. Microsoft has released security updates to address this vulnerability. Although Microsoft assesses exploitation likelihood as low, the vulnerability's nature and SharePoint's history of being targeted warrant prompt patching. No known exploits are currently reported in the wild.
AI Analysis
Technical Summary
CVE-2026-45659 is a high-severity vulnerability (CVSS 8.8) in Microsoft SharePoint caused by deserialization of untrusted data. An authenticated attacker with minimal permissions (Site Member) can remotely execute arbitrary code on the SharePoint server via network access. The vulnerability affects SharePoint Server Subscription Edition, SharePoint Server 2019, and SharePoint Enterprise Server 2016. Microsoft has released official security updates to patch this flaw. The vulnerability was discovered by a security researcher known as MEOW. Despite Microsoft's assessment that exploitation is less likely, the ease of exploitation and SharePoint's history of attacks make this a significant risk for unpatched systems.
Potential Impact
Successful exploitation allows an authenticated attacker with low privileges to execute arbitrary code remotely on the SharePoint server. This can lead to full compromise of the affected SharePoint server, potentially impacting confidentiality, integrity, and availability of data and services hosted on it. No known active exploitation has been reported at this time.
Mitigation Recommendations
Microsoft has released official security updates for SharePoint Server Subscription Edition, SharePoint Server 2019, and SharePoint Enterprise Server 2016 to address CVE-2026-45659. Organizations should apply these patches immediately to mitigate the risk. No additional mitigation steps are indicated by the vendor advisory. Patch status is confirmed as official-fix.
Microsoft SharePoint Has a New RCE Flaw. If You Haven’t Patched Yet, Go Do That.
Description
A critical remote code execution (RCE) vulnerability, tracked as CVE-2026-45659, affects Microsoft SharePoint Server versions including Subscription Edition, 2019, and Enterprise Server 2016. The flaw arises from deserialization of untrusted data, allowing an authenticated attacker with low privileges (Site Member) to execute code remotely over the network. Microsoft has released security updates to address this vulnerability. Although Microsoft assesses exploitation likelihood as low, the vulnerability's nature and SharePoint's history of being targeted warrant prompt patching. No known exploits are currently reported in the wild.
Reddit Discussion
AI-Powered Analysis
Machine-generated threat intelligence
Technical Analysis
CVE-2026-45659 is a high-severity vulnerability (CVSS 8.8) in Microsoft SharePoint caused by deserialization of untrusted data. An authenticated attacker with minimal permissions (Site Member) can remotely execute arbitrary code on the SharePoint server via network access. The vulnerability affects SharePoint Server Subscription Edition, SharePoint Server 2019, and SharePoint Enterprise Server 2016. Microsoft has released official security updates to patch this flaw. The vulnerability was discovered by a security researcher known as MEOW. Despite Microsoft's assessment that exploitation is less likely, the ease of exploitation and SharePoint's history of attacks make this a significant risk for unpatched systems.
Potential Impact
Successful exploitation allows an authenticated attacker with low privileges to execute arbitrary code remotely on the SharePoint server. This can lead to full compromise of the affected SharePoint server, potentially impacting confidentiality, integrity, and availability of data and services hosted on it. No known active exploitation has been reported at this time.
Mitigation Recommendations
Microsoft has released official security updates for SharePoint Server Subscription Edition, SharePoint Server 2019, and SharePoint Enterprise Server 2016 to address CVE-2026-45659. Organizations should apply these patches immediately to mitigate the risk. No additional mitigation steps are indicated by the vendor advisory. Patch status is confirmed as official-fix.
Technical Details
- Source Type
- Subreddit
- cybersecurity
- Reddit Score
- 0
- Discussion Level
- minimal
- Content Source
- reddit_link_post
- Post Type
- link
- Domain
- null
- Newsworthiness Assessment
- {"score":33,"reasons":["external_link","newsworthy_keywords:rce,patch","established_author","very_recent"],"isNewsworthy":true,"foundNewsworthy":["rce","patch"],"foundNonNewsworthy":[]}
- Has External Source
- true
- Trusted Domain
- false
Threat ID: 6a16c4f1e29bf47b50b119ed
Added to database: 5/27/2026, 10:18:25 AM
Last enriched: 5/27/2026, 10:18:31 AM
Last updated: 5/27/2026, 11:19:17 AM
Views: 6
Community Reviews
0 reviewsCrowdsource mitigation strategies, share intel context, and vote on the most helpful responses. Sign in to add your voice and help keep defenders ahead.
Want to contribute mitigation steps or threat intel context? Sign in or create an account to join the community discussion.
Actions
Updates to AI analysis require Pro Console access. Upgrade inside Console → Billing.
Need more coverage?
Upgrade to Pro Console for AI refresh and higher limits.
For incident response and remediation, OffSeq services can help resolve threats faster.
Latest Threats
Check if your credentials are on the dark web
Instant breach scanning across billions of leaked records. Free tier available.