Critical Path Traversal Flaws in Cisco Secure Email Gateway and Email/Web Manager
AI analysis
CVE-2026-76440 groups multiple path traversal weaknesses (CWE Pillar CWE-23) found during Cisco's internal security review of Cisco Secure Email Gateway and Cisco Secure Email and Web Manager, addressed via software hardening releases. With a CVSS 3.1 base score of 9.8 (network vector, low attack complexity, no privileges, no user interaction), a remote unauthenticated attacker could craft requests that escape intended directory boundaries to read, modify, or delete files on the appliance, potentially leading to full confidentiality, integrity, and availability impact. Any organization running an affected version of these email perimeter appliances is exposed, particularly since these gateways are designed to be internet-facing. No public proof-of-concept exists, the flaw is not in the CISA Known Exploited Vulnerabilities catalog, and no exploitation has been reported to date. Because the bugs were internally discovered, technical detail is limited and defenders should prioritize patching rather than await exploit intelligence.
What to do: Apply the software hardening release identified in Cisco's advisory for both Cisco Secure Email Gateway and Cisco Secure Email and Web Manager as soon as maintenance windows allow, given the unauthenticated 9.8 rating. Restrict the web management interface to trusted admin networks or VPN so only SMTP ports are exposed to the internet. Review appliance logs for unexpected file access, anomalous admin activity, or unfamiliar file modifications that could indicate prior probing.
Affected
| Cisco Secure Email Gateway | Affected versions not enumerated in the advisory summary; fixed in Cisco's software hardening release for this CVE |
| Cisco Secure Email and Web Manager | Affected versions not enumerated in the advisory summary; fixed in Cisco's software hardening release for this CVE |
Estimated exposure
largetens of thousands of internet-facing appliances (order 10,000-100,000 deployments) — Cisco email security gateways are perimeter appliances whose SMTP and management interfaces are frequently internet-reachable, and public scan engines have historically shown tens of thousands of Cisco ESA/SEWM instances online, though…
Order-of-magnitude estimate by the model from install counts, market share and public scan data it knows; verify before quoting.
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-2026-76440 are related to path traversal issues that are grouped under the Common Weakness Enumeration (CWE) Pillar CWE-23.