Microsoft SharePoint Has a New RCE Flaw. If You Haven’t Patched Yet, Go Do That.
Source Reddit Cybersecurity
Exploited in the wild · KEV due 4 Jul 2026 : upgrade to 16.0.5552.1002 now.
Data as of 30 Oct 2026, 11:52 UTC
- KEV deadline
- US federal agencies must patch by this date; a sensible deadline for everyone else. Other KEV due dates
- Patch
- Available – fixed in 16.0.5552.1002, 16.0.10417.20128, 16.0.19725.20280
CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H/E:U/RL:O/RC:CExploitation evidence
t = 0 is the CVE’s publication on cve.org
Disclosed: evidence found.
CVE published 22 May 2026
Detectable: no evidence on record.
No public nuclei template indexed
Weaponized: no evidence on record.
No public exploit code indexed in Metasploit or Exploit-DB
Exploited in the wildExploited: evidence found.
Listed in CISA KEV 40 days after disclosure
Observed by OffSeq MirageSeen by Mirage: no evidence on record.
No attack traffic recorded by OffSeq Mirage sensors
Timeline
CVE ID reserved
by Microsoft Corporation
, 10 days before disclosure
CVE published
on cve.org
, t = 0
In Threat Radar
record ingested
, 25 minutes after disclosure
Added to CISA KEV (opens in a new tab)
exploitation confirmed · ransomware use known
, 40 days after disclosure
KEV remediation due
US federal deadline
, 43 days after disclosure
A missing step is not evidence of safety. Sources: cve.org (opens in a new tab), CISA KEV (opens in a new tab), the Metasploit, Exploit-DB and nuclei-templates index as of 30 Oct 2026.
What to do
Upgrade Microsoft SharePoint to 16.0.5552.1002 (Enterprise Server 2016) or 16.0.10417.20128 (Server 2019) or 16.0.19725.20280 (Server Subscription Edition).
Affected software
| Product | Affected | Fixed in |
|---|---|---|
| MicrosoftMicrosoft SharePoint Enterprise Server 2016 | Affected
| Fixed in
|
| MicrosoftMicrosoft SharePoint Server 2019 | Affected
| Fixed in
|
| MicrosoftMicrosoft SharePoint Server Subscription Edition | Affected
| Fixed in
|
AI-suggested
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.
Discussion
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.
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