Microsoft has issued security updates to address a remote code execution vulnerability affecting SharePoint Server deployments, a flaw that could allow attackers to execute malicious code remotely without requiring complex attack conditions. The vulnerability, tracked as CVE 2026 45659, carries a CVSS severity score of 8.8 and has been classified by Microsoft as an important security issue. According to the company, the weakness exists due to the deserialization of untrusted data in Microsoft Office SharePoint, creating an opportunity for authenticated threat actors to exploit affected environments over a network.
Microsoft explained in its advisory that the vulnerability could be abused by attackers with only minimal access privileges. Unlike many enterprise vulnerabilities that demand administrative permissions or elevated system rights, CVE 2026 45659 can reportedly be exploited by authenticated users possessing Site Member permissions, making the attack path more accessible for malicious actors who have already gained low level access within an organization. In a network based attack scenario, the flaw enables an authenticated attacker to execute arbitrary code remotely on a SharePoint Server, potentially allowing further movement inside enterprise environments or disruption of business operations. Microsoft emphasized that the vulnerability does not require any specialized conditions or administrator access to be exploited, increasing the urgency for organizations to apply available security updates.
The security issue was discovered and responsibly reported by a researcher identified as MEOW, whom Microsoft credited for identifying the flaw. To reduce exposure risks, Microsoft released patches covering multiple versions of SharePoint currently used across enterprise environments. Affected products receiving updates include SharePoint Server Subscription Edition, SharePoint Server 2019, and SharePoint Enterprise Server 2016. Organizations running these deployments are advised to update systems as soon as possible to minimize the risk of exploitation, particularly because SharePoint continues to remain a widely deployed collaboration and document management platform inside businesses, government institutions, and educational environments.
The latest patch follows another SharePoint related security issue addressed by Microsoft only a month earlier. In April 2026, the company released fixes for a spoofing vulnerability identified as CVE 2026 32201, which carried a CVSS score of 6.5 and had reportedly been exploited in real world attacks. Although Microsoft currently assesses CVE 2026 45659 as less likely to be exploited, cybersecurity professionals often warn that vulnerabilities affecting collaboration platforms tend to attract attention due to the sensitive enterprise information they process and store. Over the years, multiple SharePoint vulnerabilities have been actively weaponized by attackers seeking unauthorized access, privilege escalation, and persistence within enterprise networks. Security experts continue to encourage organizations to prioritize patch management and monitor critical infrastructure for unusual activity, especially when vulnerabilities involve remotely executable code and widely adopted enterprise applications.
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