CVE-2026-76425: SQL Injection in Cisco ISE APIs Threatens OT Network Access Control

Executive Summary

CVE-2026-76425 is a SQL injection flaw in the APIs of Cisco Identity Services Engine, caused by insufficient validation of parameters concatenated directly into SQL queries, which lets an authenticated remote attacker read arbitrary database content and pivot through server-side request forgery. Because ISE frequently functions as the network access control authority sitting at the IT/OT boundary, compromise of this component degrades the trust anchor that decides which devices and operators are permitted onto the control network.

Technical Exposure Breakdown

The vulnerable component is the ISE API layer across the Cisco Identity Services Engine range 3.1.0 through 3.3.0, per the grounding data. The root cause is classic unsanitized input concatenation. Parameters from certain API endpoints are placed directly into SQL statements without parameterization or type enforcement. An attacker who already holds valid authentication sends a crafted request containing embedded SQL syntax to an affected endpoint.

Two outcomes follow from a successful exploit. First, arbitrary read access to the backend database, which in an ISE deployment holds policy definitions, endpoint identity data, administrative records, and potentially credential material depending on configuration. Second, server-side request forgery, which turns the ISE node into a relay for reaching internal hosts that are otherwise unreachable from the attacker's network position. In a segmented OT architecture, SSRF from a management-plane appliance is the more dangerous of the two, because ISE often has routes into zones that external attackers cannot touch directly.

The precondition is authentication. This is not an unauthenticated internet-facing break, and the CVSS score of 7.6 reflects that constraint. The practical risk is insider misuse, a compromised low-privilege API account, or a chained attack where an attacker first obtains limited API access through phishing or credential reuse and then escalates reach through the database and SSRF primitives. Patch status is listed as unknown in the grounding data, so treat remediation timing as unconfirmed and plan compensating controls accordingly.

OT Impact and Compliance Risk

ISE is an IT product, but in converged plant and utility environments it is routinely the enforcement point for 802.1X, device profiling, and posture checks that control access to the OT LAN. If the identity database can be read or manipulated indirectly, the integrity of access decisions is in question. An attacker reading policy and endpoint tables learns the exact structure of your segmentation and the identities permitted to cross it, which is reconnaissance of high value before a targeted operation.

For IEC 62443, this touches the access control and account management requirements under zone and conduit enforcement, since the mechanism that polices the conduit is itself exposed. For NERC CIP, ISE serving as an Electronic Access Control or Monitoring System would place this in scope for CIP-005 and CIP-007, meaning a confirmed exposure may carry documentation and mitigation obligations. For pipeline operators under TSA SD-02C, the same logic applies where ISE enforces access segmentation between IT and OT. Water utilities governed by AWIA 2018 risk assessment obligations should account for identity-layer exposure in their updated assessments.

Compensating Controls

Do not rely on active scanning to inventory ISE exposure in live OT segments. Aggressive API probing against the identity enforcement point can disrupt authentication for production control devices and cause access denials that look like a plant event. Use passive asset identification and configuration review instead.

Restrict API access to a dedicated management network and enforce allow-listing so only known administrative hosts can reach ISE API endpoints. Rotate and reduce the privilege of API service accounts, and audit which accounts can call the affected endpoints at all. Place a web application filtering layer or reverse proxy in front of the API and inspect for SQL metacharacters in parameter values.

A virtual patch approach is viable here. A Suricata rule concept is to inspect HTTP request bodies and URI parameters destined for ISE API endpoints for SQL control tokens such as UNION SELECT, ' OR 1=1, inline comment sequences, and stacked query delimiters, then alert or drop on match while logging the source identity for investigation. Pair detection with egress monitoring from the ISE node to catch SSRF attempts reaching into OT zones. Confirm and apply any vendor fix once version-specific guidance is published.

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