---
title: "CVE-2026-76440: Cisco Secure Email Gateway Security Hardening Release"
url: https://erroneo.us/security/cve/CVE-2026-76440/
description: "CVE-2026-76440 (Cisco Cisco Secure Email): As part of Cisco's ongoing commitment to proactive security and product quality, the Cisco Secure Email Gateway…"
type: vulnerability-record
section: "Security Digest"
date_published: 2026-09-14
date_modified: 2026-10-21
publisher: erroneo.us
author: erroneo.us Security Desk
cve: "CVE-2026-76440"
kev: false
cvss: 9.8
epss: 0.00623
license: All rights reserved. Quote with attribution and a link.
---

# CVE-2026-76440: Cisco Secure Email Gateway Security Hardening Release

**Signal:** Critical and remotely reachable. No known exploitation yet, but it is network-reachable without credentials. (Computed from CISA KEV, EPSS and CVSS; not an editorial verdict.)

## Should you act?

- No confirmed exploitation. It is not in CISA’s KEV catalog and CISA’s SSVC assessment records no known exploitation. That can change quickly after a public write-up; re-check if you are affected.
- EPSS 0.6% , percentile 49: FIRST’s model estimates a 0.6% chance of exploitation activity in the next 30 days, higher than 49% of all scored CVEs (low). EPSS is a probability, not a verdict.
- Remotely reachable with no login and no user interaction. If the vulnerable service is exposed to the internet, prioritize it.
- Editorial verdict: Act now. Cisco Secure Email Gateway: Two Exploited Root RCE Bugs — Every on-premises Secure Email Gateway below 15.5.5-014 or 16.5.0-780 can be rooted by an email and both bugs are exploited: upgrade now, and check for compromise before and after, because attackers can wipe local evidence.

## What it is

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.

## Affected products (CVE record)

- Cisco Cisco Secure Email: 14.0.0-698, 13.5.1-277, 13.0.0-392, 14.2.0-620, 13.0.5-007, 13.5.4-038, 14.2.1-020, 14.3.0-032, 15.0.0-104, 15.0.1-030, 15.5.0-048, 15.5.1-055
- Cisco Cisco Secure Email and Web Manager: 13.6.2-023, 13.6.2-078, 13.0.0-249, 13.0.0-277, 13.8.1-052, 13.8.1-068, 13.8.1-074, 14.0.0-404, 12.8.1-002, 14.1.0-227, 13.6.1-201, 14.2.0-203

## Severity

- cisco CVSS 3.1: 9.8 `CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H`

## Exploitation

- CISA KEV: not listed (no confirmed in-the-wild exploitation known to CISA).
- CISA SSVC assessment: exploitation none , automatable yes , technical impact total .
- FIRST EPSS (model of 2026-10-21): 0.62% probability of exploitation activity in the next 30 days; percentile 49.

## Sources

- [CVE.org record CVE-2026-76440](https://www.cve.org/CVERecord?id=CVE-2026-76440)
- [NVD entry CVE-2026-76440](https://nvd.nist.gov/vuln/detail/CVE-2026-76440)
- [cisco-sa-hardening-esa-dfCrfXkm](https://sec.cloudapps.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-hardening-esa-dfCrfXkm)
- [cve.org](https://www.cve.org/Media/News/item/blog/2026/06/16/Preserving-Vulnerability-Level-Identification)

---
Source page: https://erroneo.us/security/cve/CVE-2026-76440/ · Security Digest: https://erroneo.us/security/ · More: https://erroneo.us/llms.txt