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Microsoft disclosed and patched CVE-2026-58644, a critical remote code execution flaw in Microsoft SharePoint caused by insecure deserialization of untrusted data (CWE-502). The vulnerability carries a CVSS 9.8 rating and allows an unauthorized attacker to execute arbitrary code over the network by sending a crafted HTTP request, with no user interaction required.
Affected products include SharePoint Enterprise Server 2016, SharePoint Server 2019, and SharePoint Server Subscription Edition prior to patched versions published through Microsoft's security guidance. Reporting on the release said no active exploitation had been confirmed at disclosure, but warned that exploitation is likely because SharePoint is widely deployed in enterprises; organizations were urged to prioritize patching internet-exposed SharePoint systems, review access permissions, and monitor server logs for suspicious activity.
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2 events from the most recent confirmed update back to the earliest known activity.
After Microsoft confirmed CVE-2026-58644 was being exploited in the wild, CISA added the SharePoint flaw to its Known Exploited Vulnerabilities catalog and ordered federal agencies to remediate it within three days under BOD 26-04.
Microsoft published CVE-2026-58644 on 2026-07-14, disclosing a critical SharePoint remote code execution flaw caused by deserialization of untrusted data. The vulnerability affects multiple SharePoint versions and Microsoft provided a vendor advisory and patches through MSRC.
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A critical Microsoft SharePoint remote code execution flaw, **CVE-2026-50522** (`CVSS 9.8`), is being actively exploited against on-premises deployments after Microsoft released fixes for affected versions of **SharePoint Enterprise Server 2016**, **SharePoint Server 2019**, and **SharePoint Subscription Edition**. The vulnerability stems from unsafe deserialization of untrusted data and can be triggered through unauthenticated requests, making internet-facing SharePoint farms particularly exposed. Researchers reported likely real-world exploitation against honeypots, and public proof-of-concept code is now available. Reporting indicates attackers have targeted on-prem SharePoint instances and, in some cases, stolen machine keys to help preserve long-term access. The flaw was originally demonstrated during **Pwn2Own Berlin**, where exploit code was shown and shared with Microsoft before the vendor issued patches. Organizations running exposed SharePoint servers have been urged to apply the fixed versions immediately and, if patching cannot be completed at once, restrict external access and review logs for suspicious requests to SharePoint sign-in pages.
Jul 21, 2026
More than **1,370 internet-facing Microsoft SharePoint servers** were reported exposed to active exploitation of **`CVE-2026-32201`**, a spoofing vulnerability affecting SharePoint Server 2016, 2019, and Subscription Edition. Microsoft disclosed the flaw in April and CISA added it to the **Known Exploited Vulnerabilities** catalog the same day, underscoring the urgency for defenders. Although Microsoft scored the bug at **CVSS 6.5**, the risk is elevated because it can be exploited **remotely without authentication** against exposed on-premises deployments, potentially allowing attackers to impersonate users, access or alter sensitive content, steal credentials, and move laterally inside victim environments. The exposure comes amid broader concern over SharePoint security, including Microsoft's disclosure of **`CVE-2026-26106`**, a **remote code execution** vulnerability in SharePoint Server, and earlier reporting that a **China-linked threat actor** was involved in SharePoint attacks, according to Mandiant. The concentration of exposed systems was highest in the **United States**, and the combined reporting points to sustained attacker interest in SharePoint as a route into enterprise networks. Organizations were urged to apply Microsoft's available updates, reduce direct internet exposure of SharePoint servers, and closely monitor authentication and document-access activity for signs of compromise.
Jun 29, 2026
Microsoft disclosed and patched several **remote code execution** vulnerabilities affecting **Exchange Server** and **SharePoint Server**, including Exchange flaws tracked as `CVE-2023-21706`, `CVE-2023-28310`, and `CVE-2023-36439`, alongside SharePoint issues `CVE-2026-33110`, `CVE-2026-33112`, and `CVE-2026-40368`. The SharePoint vulnerabilities were tied to **deserialization of untrusted data** and were rated **Important**, with CVSS scores of **8.8** for `CVE-2026-33110` and `CVE-2026-33112`, and **8.0** for `CVE-2026-40368`. Microsoft said `CVE-2026-33110` could let an authenticated attacker with at least **Site Member** permissions execute code remotely on a vulnerable SharePoint Server, while `CVE-2026-33112` required at least **Site Owner** privileges to inject and run arbitrary code. For `CVE-2026-40368`, exploitation involved a client connecting to a malicious server, potentially leading to code execution on the client. Microsoft reported that the SharePoint flaws were **not publicly disclosed** and **not exploited in the wild** at publication, assessed exploitation as less likely, and released fixes, including a shared KB update for **SharePoint Server 2016** and **SharePoint Enterprise Server 2016**.
Jun 29, 2026