Security Resilience

CVE-2026-76519

Path Traversal in Cisco Asyncos 15.0 – 15.5.5-014

CISA KEVActive ExploitationEUVD ExploitedPath Traversal
Published
14 October 2026
Modified
15 October 2026
KEV Added
14 October 2026
Patch / advisory
View advisory
CVSS Score v3.1 9.8
Click a component to see what it means
Raw vectorCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
EPSS Score 0.017 77th percentile
Risk Priority 97 floored blend · peak EPSS

CVSS and EPSS are reproduced from their sources (NVD, FIRST EPSS). Risk Priority is our own derived reading, not an NVD score.

Summary

CVE-2026-76519 is a critical-severity Relative Path Traversal (CWE-23) vulnerability in Cisco Asyncos. Its CVSS base score is 9.8 (Critical).

Operationally, exploitation aligns with the MITRE ATT&CK technique Data Obfuscation (T1001); ranked in the top 23% of CVEs by exploit likelihood; CISA has added it to the Known Exploited Vulnerabilities catalog.

The strongest mitigations our analysis identified map to SA-8 (Security and Privacy Engineering Principles) and SI-10 (Information Input Validation) — see the control section below for these in your framework.

OWASP Top 10 for Web (2025)

A01:2025 Broken Access Control

EU & UK References

Vulnerability Data

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…

more

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.

CWE(s)
CWE-23
KEV Date Added
14 October 2026

Related Threats

MITRE ATT&CK Enterprise Techniques

T1001 Data Obfuscation Command And Control
Adversaries may obfuscate command and control traffic to make it more difficult to detect.
attack.mitre.org →
T1001.003 Protocol or Service Impersonation Command And Control
Adversaries may impersonate legitimate protocols or web service traffic to disguise command and control activity and thwart analysis efforts.
attack.mitre.org →
T1003.002 Security Account Manager Credential Access
Adversaries may attempt to extract credential material from the Security Account Manager (SAM) database either through in-memory techniques or through the Windows Registry where the SAM database is stored.
attack.mitre.org →
T1003.005 Cached Domain Credentials Credential Access
Adversaries may attempt to access cached domain credentials used to allow authentication to occur in the event a domain controller is unavailable.
attack.mitre.org →
T1003.007 Proc Filesystem Credential Access
Adversaries may gather credentials from the proc filesystem or `/proc`.
attack.mitre.org →
T1005 Data from Local System Collection
Adversaries may search local system sources, such as file systems, configuration files, local databases, virtual machine files, or process memory, to find files of interest and sensitive data prior to Exfiltration.
attack.mitre.org →
Derived from this CVE’s CWE(s) via the direct CWE→ATT&CK cross-walk.

CVEs Like This One

CVE-2026-76461Same product: Cisco Asyncosboth on KEV
CVE-2024-20392Same product: Cisco Asyncos
CVE-2024-20257Same product: Cisco Asyncos
CVE-2024-20429Same product: Cisco Asyncos
CVE-2024-20310Same vendor: Cisco
CVE-2026-76424Same vendor: Cisco
CVE-2025-20393Same product: Cisco Asyncosboth on KEV
CVE-2025-64446Shared CWE-23both on KEV
CVE-2026-34926Shared CWE-23both on KEV
CVE-2021-40870Shared CWE-23both on KEV

Affected Assets

cisco
asyncos
15.0 — 15.5.5-014 · 16.0 — 16.5.0-780

Mitigating Controls

Control response

Prevent
Stop it (NIST 800-53)

—

Detect
Catch it (NIST detect / respond)

—

Harden
Shrink the surface (DISA STIG)

—

Validate
Prove the fix (OWASP ASVS)
  • V5.3.2

Mitigating Controls (NIST 800-53 r5) AI

SA-8 Security and Privacy Engineering Principles partial match

Secure-engineering principles require safe pathname construction and input neutralization before any file operation.

SI-10 Information Input Validation partial match

Explicit validation of path inputs stops .. sequences from ever being interpreted by the file system.

Mitigating Controls (NIST CSF 2.0) AI

Derived directly from the weakness types (CWEs) cited in the NVD entry via our AI-authored CWE→CSF cross-walk (authority under review) — links open the control.

PR.PS-06 partial match
blocks

Secure SDLC practices directly require input validation and path sanitization that prevent relative traversal.

Mitigating Controls (ISO/IEC 27001:2022 Annex A) AI

Derived directly from the weakness types (CWEs) cited in the NVD entry via our AI-authored CWE→ISO cross-walk (authority under review) — links open the control.

A.5.14 Information transfer partial match
removes
A.5.15 Access control partial match
removes
A.5.16 Identity management partial match
removes
A.5.17 Authentication information partial match
removes
A.5.18 Access rights partial match
removes
A.8.10 Information deletion partial match
removes

References