How do you patch or mitigate CVE-2025-22457 (Ivanti Connect Secure, Policy Secure, and ZTA Gateways Stack-Based Buffer Overflow)?

What the fix means in practice for Ivanti appliances

CVE-2025-22457 is a stack-based buffer overflow in Ivanti Connect Secure, Policy Secure, and ZTA Gateways. The practical response is not just “patch it”, but to confirm every exposed instance, apply the vendor security update or documented mitigation, and treat any internet-facing deployment as urgent until the device is either updated or removed from exposure.

Because this is an edge security product, the highest-risk condition is an appliance that sits directly on the internet and can be reached before compensating controls are in place. If you cannot confirm the device is patched or mitigated, assume it is still within the vulnerability’s blast radius and work from that assumption rather than waiting for a scan result to prove compromise.

For broader version, fix, and rollout details, use the vendor advisory alongside the CISA Known Exploited Vulnerabilities Catalog as the authoritative sources of truth.

How to confirm exposure and scope the response

Start by building a complete inventory of every Ivanti Connect Secure, Policy Secure, and ZTA Gateway instance, including forgotten lab systems, secondary regions, and remote access appliances that are not managed through the main patch cadence. A vulnerability like this is often missed because it lives on infrastructure teams do not scan with the same frequency as endpoints or servers.

Once you have the list, verify which systems are actually internet reachable, which are behind another security layer, and which are already in maintenance or replacement paths. That distinction matters because the remediation decision changes quickly once an appliance is externally exposed and serving real user traffic.

When the product is still required, prioritise the shortest path to the vendor update or documented mitigation. When the appliance cannot be updated in time, isolate it by removing direct internet exposure, tightening access paths, or taking it out of service. If the box is part of a remote-access tier, use the opportunity to check whether a more durable replacement path is available, such as shifting users off the appliance rather than repeatedly relying on emergency exceptions.

What to do while patching is pending

If patching must wait, the goal is to reduce exploitability and limit the damage of a successful buffer overflow. That usually means shrinking the reachable surface, restricting who can reach the device, and watching for signs that the appliance was already used as an entry point before the fix was applied.

In practice, that also means preserving logs, configuration state, and timestamps before making emergency changes. For an edge gateway, forensic value can disappear quickly once a restart, rollback, or emergency reconfiguration occurs, so capture what you can first if compromise is even a possibility.

If the appliance exposes credentials, session material, or administrative access during the incident window, plan for rotation after remediation. The question is not only whether the overflow is patched, but whether an attacker may have used it to move from the gateway into downstream authentication paths or internal services.

Risk and Threat Considerations

An internet-facing stack overflow on a remote-access gateway is high consequence because it can become a direct foothold into the trust boundary that protects the rest of the environment. The main risk is not just crash or denial of service, but pre-authenticated or low-friction execution conditions that can lead to further access if the device is already exposed and managed loosely.

Failure mechanism: A memory corruption flaw on a perimeter appliance can let an attacker trigger code execution or service disruption before normal authentication and authorization controls are effective.

Impact: Successful exploitation can expose remote access infrastructure, internal sessions, credentials, and adjacent systems that depend on the gateway as a trust anchor.

Practitioner Guidance

What to prioritise: Treat internet-facing appliances first, then authenticated management surfaces, then internal-only deployments. If you have more than one Ivanti instance, focus on the one that is both reachable and business critical, because that is where exposure and operational pressure will be highest.

What to verify: Confirm the appliance model, deployment role, current exposure, and whether the documented mitigation has actually been applied. Do not rely on “scheduled for patching” as a control state; for a KEV-listed issue, a planned change is not risk reduction until it is live.

Decision rule: If the device cannot be updated immediately, remove internet exposure or take it out of service rather than letting it remain an exception. The acceptable exception is temporary outage or controlled isolation, not continued exposure with a promise to patch later.

Practitioner takeaway: For a gateway CVE in the KEV catalog, the real control is speed of exposure reduction, not patch intent, so remediation should be judged by whether the vulnerable service is still reachable.

Related resources from NHI Mgmt Group

• Guide: VPN Security Guide
• CVE-2025-22457 (Ivanti Connect Secure, Policy Secure, and ZTA Gateways Stack-Based Buffer Overflow)
• CVE-2025-0282 (Ivanti Connect Secure, Policy Secure, and ZTA Gateways Stack-Based Buffer Overflow)
• How do you patch or mitigate CVE-2025-53521 (F5 BIG-IP Stack-Based Buffer Overflow)?
• How do you patch or mitigate CVE-2025-32756 (Fortinet Multiple Products Stack-Based Buffer Overflow)?