CVE-2026-76519: asyncos Path Traversal

Description

A vulnerability in the Advanced Malware Protection (AMP) feature of Cisco Secure Email Gateway could allow an unauthenticated, remote attacker to write arbitrary files on the underlying operating system. This vulnerability is due to improper handling of email attachments when the file reputation service is enabled. An attacker could exploit this vulnerability by sending an email that contains a crafted attachment through an affected device. A successful exploit could allow the attacker to write arbitrary files and execute commands with root privileges on the underlying operating system.

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CVSS v3.1 Score

9.8

CRITICAL

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

EPSS — Exploit Prediction

0.0157

Probability of exploitation

0.75%

Percentile rank

EPSS estimates the probability that this vulnerability will be exploited in the wild within the next 30 days. A higher score means more likely to be exploited.

CISA Known Exploited Vulnerability

This vulnerability is actively exploited in the wild.

Added: Oct 14, 2026 Remediation due: Oct 17, 2026

Weakness Type (CWE)

CWE-23 CWE-23

Affected Products

Vendor	Product	Versions
cisco	asyncos	15.0 — 15.5.5-014
cisco	asyncos	16.0 — 16.5.0-780
cisco	secure_email_gateway_virtual_appliance_c100v	All
cisco	secure_email_gateway_virtual_appliance_c300v	All
cisco	secure_email_gateway_virtual_appliance_c600v	All
cisco	secure_email_gateway_c195	All
cisco	secure_email_gateway_c395	All
cisco	secure_email_gateway_c695	All

References

Advisories & Patches

https://sec.cloudapps.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-esa-afw-zqYJkjxp

Other References

https://www.cisa.gov/known-exploited-vulnerabilities-catalog?field_cve=CVE-2026-76519

Frequently Asked Questions

What is CVE-2026-76519? +

A vulnerability in the Advanced Malware Protection (AMP) feature of Cisco Secure Email Gateway could allow an unauthenticated, remote attacker to write arbitrary files on the underlying operating system. This vulnerability is due to improper handling of email attachments when the file reputation service is enabled. An attacker could exploit this vulnerability by sending an email that contains a crafted attachment through an affected device. A successful exploit could allow the attacker to write arbitrary files and execute commands with root privileges on the underlying operating system. It has a CVSS v3.1 base score of 9.8 (CRITICAL). This vulnerability is listed in CISA's Known Exploited Vulnerabilities catalog, indicating active exploitation in the wild.

How severe is CVE-2026-76519? +

CVE-2026-76519 has a CVSS v3.1 score of 9.8 out of 10, rated CRITICAL. This is a critical vulnerability that should be patched immediately. The EPSS score is 0.0157, placing it in the 1th percentile for exploitation probability.

What products are affected by CVE-2026-76519? +

CVE-2026-76519 affects products from cisco, specifically: asyncos, secure_email_gateway_c195, secure_email_gateway_c395, secure_email_gateway_c695, secure_email_gateway_virtual_appliance_c100v, secure_email_gateway_virtual_appliance_c300v, secure_email_gateway_virtual_appliance_c600v. Check the affected products table above for specific version ranges.

How do I check if I'm vulnerable to CVE-2026-76519? +

You can use Secably's free Website Scanner to check your website for known vulnerabilities. For infrastructure scanning, use the Port Scanner to identify exposed services that may be affected. Check the vendor advisories linked above for specific patch and version information.

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