After a proof-of-concept (PoC) code was released, threat actors started to take advantage of a recently discovered Microsoft SharePoint vulnerability.
CVE-2026-55040 (CVSS score: 9.1), a critical security feature bypass resulting from inadequate authentication, is the vulnerability in question. As part of their July 2026 Patch Tuesday upgrades, Microsoft fixed it.
Because this weakness permits impersonation, the authentication mechanism might be circumvented, Microsoft stated in a warning regarding the problem last month. An attacker may be able to reveal files and alter data by taking advantage of this vulnerability, although they are unable to affect the system’s availability.
Threat actors are using a Proof of Concept (PoC) exploit that Rapid7 released earlier this week, according to Defused Cyber, which further suggests that new vulnerabilities are being exploited in actual assaults.
If CVE-2026-55040 is successfully exploited, an unauthenticated attacker may circumvent authentication on a susceptible SharePoint server and carry out arbitrary actions as a SharePoint site administrator or user read more about Attackers Exploit SharePoint Authentication Bypass After Public PoC Release
Get up to date on the latest cybersecurity news and enhance your knowledge of cybersecurity with our thorough coverage of the dangers, breaches, and solutions.