External risk intelligence

Cisco Secure Email Gateway SQL Injection Command Execution

CVE advisoryKnown Exploit

CVE-2026-76461

The affected product is a Secure Email Gateway, which is designed to be internet-facing to receive and process incoming email traffic. It acts as an edge service that must be reachable by external mail servers to function in its primary role.

SQL Injection

Cisco Asyncos

before 15.5.5-01416.0 to before 16.0.4-30216.5 to before 16.5.0-780

Halo Surface Signal: 5 out of 5 — more likely to be public-facing.

External exposure likelihood

Horizon Alert

Summary of the vulnerability and why it matters

A critical vulnerability has been identified in Cisco's Secure Email Gateway software, specifically within its email parsing capabilities. This issue could potentially allow unauthorized remote attackers to gain root-level control over the underlying operating system by sending specially crafted emails. The main concern is confirming relevance and exposure to this type of gateway.

Allows attackers to run unauthorized commands.
Critical flaw affects internet-facing email security.
Assess if this email gateway is in use.

Attack Path

How an attacker could exploit the issue

An unauthenticated attacker could send a specially crafted email to a vulnerable Cisco Secure Email Gateway. This malicious email, containing embedded SQL commands, would be processed by the gateway's email parsing logic. If the validation is insufficient, the SQL commands could be executed, potentially leading to the attacker gaining root-level control over the device.

Attacker sends malicious email.
Email parsing logic is triggered.
Arbitrary command execution occurs.

Live Threat

Current exploitation, exposure, and threat context

This vulnerability could affect the underlying operating system of the Cisco Secure Email Gateway, allowing an attacker to execute commands with root privileges. This could occur when the system processes a specially crafted email.

Affected system: Cisco Secure Email Gateway.
Exposure: Malicious email processing.
Consequence: System compromise and command execution.

Operational Fix

Recommended remediation, mitigation, and detection steps

This critical vulnerability in Cisco Secure Email Gateway affects its email parsing, potentially allowing remote attackers to execute commands as root. The Cisco Product Security Incident Response Team (PSIRT) and your infrastructure or platform teams are likely responsible for managing this. The first practical step is to confirm the presence and accessibility of affected devices, identify business-critical instances, and then plan remediation actions.

Identify accountable Cisco Secure Email Gateway owners.
Verify device exposure and criticality.
Coordinate vendor-guided remediation.

Supplementary metadata

CVSS vector

Validate whether this threat affects your internet-facing exposure.

Halo Threat Intelligence helps prioritize remediation with Halo Surface Signal and H/A/L/O context. Start exposure validation with a free external attack surface trial.

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Frequently asked questions

What is Cisco Secure Email Gateway?

Cisco Secure Email Gateway is a specialized network appliance running AsyncOS. Its primary purpose is to filter and inspect incoming email traffic at the network edge before it reaches an organization's internal mail servers, acting as a critical security checkpoint.

What does CVE-2026-76461 mean?

This CVE represents a SQL injection vulnerability (CWE-89) in the device's email parsing logic. It occurs when the software improperly handles malicious SQL statements embedded within an email, which can inadvertently trigger the execution of unauthorized commands at the root level of the operating system.

How is this vulnerability triggered?

An attacker triggers this by sending a specially crafted email designed to exploit parsing weaknesses. Merely hosting the software is not the trigger; the code must actively process the malicious email message for the flaw to manifest as command execution.

Why is this a high-priority risk?

According to Halo Surface Signal, these gateways are designed to be internet-facing to receive external mail, making them naturally exposed to remote attackers. Because the gateway must remain reachable by the public internet to function, any unpatched device is a direct entry point for potential system-wide compromise.

What are the first steps to take?

Start by identifying all Cisco Secure Email Gateway instances within your environment. Once mapped, verify their accessibility and confirm ownership with the relevant infrastructure teams to coordinate vendor-guided updates or security configurations provided by Cisco.

References

Written by Nicholas Merritt

Nicholas Merritt is VP of Security Solutions at Halo Security. With more than 25 years across application security, vulnerability prioritization, and offensive security, he helps teams translate threat data into practical exposure validation and remediation focus. He authors Halo Threat Intelligence CVE advisories using Halo Surface Signal and H/A/L/O context to prioritize internet-facing risk.