CVE-2026-61613: Cursor: Cloud Agent Browser Sandbox Escape

Severity: high (CVSS 7.7 v4.0)
Exploited in the wild: not listed in CISA KEV
EPSS: 0.7% probability of exploitation in the next 30 days
Public exploit or detection template: none known
Published: 2026-07-15 · updated 2026-07-21
Weakness: CWE-306

Description

Cursor is a code editor built for programming with AI. Prior to the Cloud Agent fix on 03/31/2026, browser-enabled Cursor Cloud Agent sessions allowed attacker-controlled web content to connect from inside the agent container to an unauthenticated local agent endpoint, enabling code execution within the affected Cloud Agent sandbox or session and access to files, repository contents, environment variables, credentials, and GitHub App access tokens available to that session. This issue was fixed on 03/31/2026 by requiring authentication for the relevant agent endpoint.

Affected products

cursor: before 03/31/2026

References

https://github.com/cursor/cursor/security/advisories/GHSA-whx2-4gvm-m3r3

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