ServiceNow Patches Critical AI Platform Flaw Allowing Unauthenticated User Impersonation

Jan 13, 2026Ravie LakshmananVulnerability / SaaS Security

ServiceNow has disclosed details of a now-patched critical security flaw impacting its ServiceNow AI Platform that could enable an unauthenticated user to impersonate another user and perfo

Jan 13, 2026Ravie LakshmananVulnerability / SaaS Security

ServiceNow Patches Critical AI Platform Flaw Allowing Unauthenticated User Impersonation

ServiceNow has disclosed details of a now-patched critical security flaw impacting its ServiceNow AI Platform that could enable an unauthenticated user to impersonate another user and perform arbitrary actions as that user.

The vulnerability, tracked as CVE-2025-12420, carries a CVSS score of 9.3 out of 10.0

“This issue […] could enable an unauthenticated user to impersonate another user and perform the operations that the impersonated user is entitled to perform,” the company said in an advisory released Monday.

The shortcoming was addressed by ServiceNow on October 30, 2025, by deploying a security update to the majority of hosted instances, with the company also sharing the patches with ServiceNow partners and self-hosted customers.

The following versions include a fix for CVE-2025-12420 –

Now Assist AI Agents (sn_aia) – 5.1.18 or later and 5.2.19 or later
Virtual Agent API (sn_va_as_service) – 3.15.2 or later and 4.0.4 or later

ServiceNow credited Aaron Costello, chief of SaaS Security Research at AppOmni, with discovering and reporting the flaw in October 2025. While there is no evidence that the vulnerability has been exploited in the wild, users are advised to apply an appropriate security update as soon as possible to mitigate potential threats.

The disclosure comes nearly two months after AppOmni revealed that malicious actors can exploit default configurations in ServiceNow’s Now Assist generative artificial intelligence (AI) platform and leverage its agentic capabilities to conduct second-order prompt injection attacks.

The issue could then be weaponized to execute unauthorized actions, enabling attackers to copy and exfiltrate sensitive corporate data, modify records, and escalate privileges.

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AndyC

Andy Curtis is an award-winning security consultant, researcher and public speaker. He has been working in the computer security industry since the early 1990s, having been employed by state and federal government, leading healthcare and banking providers across three continents. He has given talks about computer security for some of the world’s largest companies, worked with law enforcement agencies on investigations into hacking groups, and is a regular voice on TV and radio explaining IT security threats.

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