Security Digest · Vulnerability record
CVE-2026-76440: Cisco Secure Email Gateway Security Hardening Release
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.
CVSS 9.8 Critical EPSS 0.6% · p49 Act now
Should you act?
Critical and remotely reachable
No known exploitation yet, but it is network-reachable without credentials. This signal is computed from CISA KEV, EPSS and CVSS data; it is not an editorial verdict.
- 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.
Weakness type: CWE-23.
Product: Cisco Cisco Secure Email · Assigned by: cisco · Published: 2026-09-14
Affected and fixed versions
| Vendor | Product | Affected versions (per 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 scores
| Scored by | CVSS | Score | Vector |
|---|---|---|---|
| cisco | 3.1 | 9.8 Critical | CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H |
- Attack vector: network (remotely reachable)
- Attack complexity: low
- Privileges required: none (no login)
- User interaction: none
- Scope: unchanged
CVSS measures how bad a flaw is if exploited, not how likely exploitation is. Read it next to the exploitation data below.
Exploitation and urgency
- 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.
Timeline
- — CVE record published by cisco
- — erroneo.us brief: Cisco Secure Email Gateway: Two Exploited Root RCE Bugs
- — CVE record last updated
Sources and references
Original sources first. Version and fix details should always be confirmed against the vendor or project advisory.
Vulnerability records
- CVE.org record CVE-2026-76440 cve.org
- NVD entry CVE-2026-76440 nvd.nist.gov
Other references from the CVE record and advisory
- cisco-sa-hardening-esa-dfCrfXkm sec.cloudapps.cisco.com
- cve.org cve.org