The US Cybersecurity and Infrastructure Security Agency (CISA) added CVE-2026-76519, a Cisco Secure Email Gateway Relative Path Traversal Vulnerability, to its Known Exploited Vulnerabilities (KEV) catalog on October 14, 2026. CISA adds a flaw to the catalog when it has reliable evidence that attackers are exploiting it in the wild.
What CISA says
Cisco Secure Email Gateway contains a relative path traversal vulnerability that could allow an unauthenticated, remote attacker to write arbitrary files on the underlying operating system.
— CISA KEV catalog entry for CVE-2026-76519
Key facts
| CVE | CVE-2026-76519 |
|---|---|
| Vendor / product | Cisco Secure Email Gateway |
| Added to KEV | October 14, 2026 |
| Federal deadline | October 17, 2026 |
| Known ransomware use | Unknown |
| Weakness (CWE) | CWE-23 |
| CISA forensic triage | Yes |
| CVSS base score (NVD) | 9.8 Critical |
| CVSS vector | CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H |
Who has to act, and by when
US federal civilian executive branch agencies are required to remediate the vulnerability by October 17, 2026. CISA urges all organizations to prioritize KEV-listed flaws as part of their vulnerability management.
CISA’s required action for this entry:
Apply mitigations in accordance with vendor instructions, ensuring compliance with CISA’s BOD 26-04 Prioritizing Security Updates Based on Risk (see URL in Notes) guidance and CISA’s “Forensics Triage Requirements” (see URL in Notes). Follow applicable BOD 26-04 guidance for cloud services or discontinue use of the product if mitigations are unavailable. Stakeholders are responsible for evaluating each asset's internet exposure and ensuring adherence to BOD 26-04 patching guidelines.
References
- CISA Known Exploited Vulnerabilities Catalog https://www.cisa.gov/known-exploited-vulnerabilities-catalog
- NIST NVD — CVE-2026-76519 https://nvd.nist.gov/vuln/detail/CVE-2026-76519
- sec.cloudapps.cisco.com https://sec.cloudapps.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-esa-afw-zqYJkjxp
- www.cisa.gov https://www.cisa.gov/news-events/directives/bod-26-04-prioritizing-security-updates-based-risk
- www.cisa.gov https://www.cisa.gov/news-events/directives/bod-26-04-implementation-guidance-prioritizing-security-updates-based-risk