Critical CosmosEscape Flaw Breaks Customer Isolation in Azure Cosmos DB
A critical vulnerability named CosmosEscape allowed attackers to escape the restricted Gremlin API environment and execute arbitrary code on the DB Gateway component of Azure Cosmos DB. The flaw exploited weaknesses in .NET reflection protections, enabling file read/write operations and command execution that ultimately yielded the Cosmos Master Key. With this global signing key, an attacker could retrieve the primary key for any customer account and gain full read/write access. The exploit also exposed the Config Store containing account names, subscription identifiers, tenant details, and network rules. Even network-isolated and private instances remained vulnerable because the DB Gateway itself enforced those restrictions. Internal Microsoft services including Entra ID, Teams, and Copilot rely on Cosmos DB, amplifying the potential impact of the issue.
BoletimSecJul 31, 2026Translated from Portuguese