Description

As part of Cisco's ongoing commitment to proactive security and product quality, the Cisco Secure Email Gateway and Cisco Secure Email and Web Manager engineering team has conducted a comprehensive internal security review. This review resulted in software hardening releases that address multiple internally discovered vulnerabilities. The vulnerabilities tracked by CVE-2026-76443 are related to issues with improper neutralization that are grouped under the Common Weakness Enumeration (CWE) Pillar CWE-707.

Executive Summary

Technical Details

Mitigations

References

Additional Metadata

{
  "score": "9.8",
  "pubDate": "2026-09-14T17:17:50.970Z",
  "pubdate": "2026-09-14T17:17:50.970Z",
  "executiveSummary": "Cisco Secure Email Gateway and Cisco Secure Email and Web Manager are affected by an improper neutralization vulnerability identified as CVE-2026-76443.\nThis vulnerability, categorized under CWE-707 (Improper Neutralization), involves the failure to adequately sanitize or encode input data before processing.\nThe flaw was identified during an internal security review and impacts the integrity and security posture of the affected appliances.\nExploitation of this vulnerability may allow an attacker to bypass security controls, inject malicious inputs, or manipulate system processes depending on the specific context of the neutralization failure.\nThe risk implications include potential unauthorized data handling, system instability, or the execution of unintended commands within the application environment.\nGiven the role of these gateways in email and web traffic management, the vulnerability presents a significant risk to the security infrastructure.\nUsers are encouraged to review software hardening releases to address these internally identified security gaps.",
  "technicalDetails": "The vulnerability CVE-2026-76443 is rooted in improper neutralization practices, as defined under the CWE-707 pillar. This occurs when the Cisco Secure Email Gateway or Cisco Secure Email and Web Manager software fails to perform adequate input validation or output encoding on data received from untrusted sources before such data is utilized in critical functions or rendered by the system.\nAt a technical level, the issue resides in the handling of input strings that are subsequently interpreted by the application or its underlying processing components. Because the system does not properly neutralize special characters, control sequences, or formatting tags, an attacker can supply crafted input designed to violate the intended logic of the application. This effectively bypasses the application's input filtering mechanisms.\nThe attack flow generally involves the submission of malicious payload vectors through interfaces processed by the vulnerable component. Once received, the application fails to distinguish between legitimate data and executable or control commands. This improper neutralization allows the injected payload to be processed as part of the application's logic, potentially leading to unauthorized data modification, security policy bypasses, or system disruption.\nThe vulnerable component likely involves the input processing pipeline where user-supplied information is parsed and stored or executed. Without appropriate neutralization, the application treats user-controlled content as trusted instructions or structural commands. This can manifest as cross-site scripting (XSS), command injection, or other secondary injection attacks, depending on where the data is reflected or executed.\nThe post-exploitation impact depends on the specific context of the neutralization failure; however, successful exploitation can result in a loss of system integrity. Because these products function as security gateways, an attacker successfully exploiting this flaw could potentially compromise the filtering logic, manipulate administrative interfaces, or exfiltrate sensitive configuration data if the input is processed with elevated privileges.\nThis internal discovery highlights a fundamental weakness in the processing of external data streams. Remediation involves ensuring that all input, including headers, parameters, and form fields, is strictly validated against a known-good allowlist and that all output is contextually encoded to prevent the interpreter from mistakenly executing injected payloads."
}