ServiceNow patches CVE-2026-6875, a critical unauthenticated sandbox escape in its AI Platform
Disclosed July 13, the flaw let unauthenticated users escape the server-side script sandbox; the fix ships as a 'Guarded Script' runtime across Brazil, Australia, Zurich and Yokohama releases.
ServiceNow disclosed CVE-2026-6875 on July 13, 2026, a critical unauthenticated sandbox-escape vulnerability in the ServiceNow AI Platform, and shipped a fix via a new "Guarded Script" runtime. Per the advisory (ServiceNow support, KB3137947; tracked at NowIsor): "Under certain circumstances the flaw allows an unauthenticated user to escape the server-side script sandbox and execute code within the ServiceNow platform... The fix ships as Guarded Script."
Context
ServiceNow's platform executes customer scripts inside a server-side sandbox — the same extensibility layer that powers its AI agents and workflow automation. A sandbox escape there is not merely a platform bug; it is a concrete instance of agent-platform runtime risk at a moment when enterprises are deploying autonomous workflow agents on Now at scale.
What changed
- Vulnerability disclosed: CVE-2026-6875, unauthenticated server-side script sandbox escape enabling code execution within the platform.
- Fix mechanism: "Guarded Script," a runtime replacement for the legacy sandbox.
- Fixed versions: Brazil EA/GA, Australia Patch 2, Zurich Patch 7b and 9, Yokohama Patch 12 HF1b and 13, per the advisory tracking.
- Rollout: phased enforcement for authenticated traffic over approximately four weeks following disclosure.
Why it matters
Enterprises connect ServiceNow agents to HR, IT and customer systems with broad permissions; an unauthenticated RCE on the platform is a worst-case exposure for exactly the autonomy enterprises have been granting. The Guarded Script approach — replacing the runtime rather than patching individual escape paths — signals ServiceNow treats sandbox integrity as architectural, not incremental. Security teams running agents on affected versions should treat patching as urgent.
Details
The vulnerability required no authentication, widening the exposed population to internet-facing instances. The phased ~4-week enforcement for authenticated traffic balances compatibility risk against closure speed — customers with heavy custom scripting should test against Guarded Script before enforcement reaches their instances.
Limitations and caveats
Technical detail beyond the advisory summary is limited; no public exploit or in-the-wild exploitation was reported in the sources reviewed. Version coverage above reflects the advisory as tracked by NowIsor; customers should confirm their exact patch level in ServiceNow's KB3137947.
Sources
- ServiceNow Support — KB3137947 (official advisory)
- NowIsor: CVE-2026-6875 tracker (CVE tracker)
*Update note: Published July 13, 2026; last reviewed July 22, 2026. Phased enforcement continues into August.*
Sources
- ServiceNow Support (KB3137947) — official
- NowIsor CVE-2026-6875 tracker — aggregator
Drafted with AI assistance from source briefs; reviewed for citation completeness and label accuracy.