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CVE-2025-53786 is a high-severity elevation-of-privilege vulnerability affecting Microsoft Exchange Server 2016, Exchange Server 2019, and Exchange Server Subscription Edition when deployed in hybrid configurations with Exchange Online. The issue arises from the legacy hybrid trust model in which the on-premises Exchange environment and Exchange Online share the same service principal identity. In vulnerable deployments, an attacker who has already obtained administrative access to the on-premises Exchange server can abuse this shared service principal trust to escalate privileges into the connected cloud tenant and gain control over Exchange Online functionality. Microsoft documented the issue in connection with April 2025 Exchange hybrid security changes and associated hotfixes, and recommends migration away from the shared service principal model to a Dedicated Exchange Hybrid App.
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No valid public exploits. Mallory filtered out 1 candidate as fakes, detection scripts, or README-only repos.
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Vendor-confirmed product mapping. Mallory continuously reconciles this list against your asset inventory.
218 sources tracked across advisories, community write-ups, and news. New activity surfaces here as Mallory finds it.
Microsoft Exchange Server vulnerability in hybrid deployments enabling elevated privileges/silent cloud access (per title/summary).
An elevation of privilege vulnerability in Microsoft Exchange Server Hybrid Deployment reported as exploited.
A high-severity Microsoft Exchange hybrid vulnerability enabling lateral movement from on-premises Exchange into Microsoft cloud environments after an attacker gains administrative access, potentially resulting in total domain compromise.
A post-exploitation vulnerability referenced by Microsoft as a security motivation for moving Exchange hybrid deployments away from the Exchange Online shared service principal toward a dedicated Exchange hybrid app.
Query your assets running an affected version, and investigate the blast radius.
Every observed campaign linking this CVE to a named adversary.
Malware families riding this exploit, with evidence and IOCs.
YARA, Sigma, Snort, and vendor rules, auto-deployed to your SIEM.
Cross-references every affected SKU, including bundled OEM variants.
Community discussion across Reddit, Mastodon, and other social sources.