A critical cross-site scripting (XSS) vulnerability (CVE-2026-42897) in Microsoft Exchange Server is being exploited by attackers, Microsoft warned on Thursday. A permanent fix is still in the works. In the meantime, Microsoft provided temporary mitigations. About CVE-2026-42897 CVE-2026-42897 affects on-premises versions of Microsoft Exchange Server: Subscription Edition RTM, 2019, and 2016. Exchange Online is not affected. Flagged by an anonymous researcher, the vulnerability allows an unauthorized attacker to perform spoofing over a network. “An attacker … More →
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