Cyber Resilience

CVE-2026-20065

Cisco Unified Threat Defense Snort Intrusion Prevention System Engine 17.10.1a … 17.9.8

Published
04 March 2026
Modified
19 August 2026
Patch / advisory
View advisory
CVSS Score v3.1 5.8
Click a component to see what it means
Raw vectorCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:N/I:N/A:L
EPSS Score 0.0037 29th percentile
Risk Priority 46 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-2026-20065 is a medium-severity Improper Locking (CWE-667) vulnerability in Cisco Unified Threat Defense Snort Intrusion Prevention System Engine. Its CVSS base score is 5.8 (Medium).

Operationally, exploitation aligns with the MITRE ATT&CK technique Endpoint Denial of Service (T1499); ranked at the 29th percentile by exploit likelihood (below the median); it is not currently listed in the CISA KEV catalog.

EU & UK References

Vulnerability Data

Multiple Cisco products are affected by a vulnerability in the Snort 3 Detection Engine that could allow an unauthenticated, remote attacker to cause the Snort 3 Detection Engine to restart, resulting in an interruption of packet inspection. This vulnerability is…

more

due to an error in the binder module initialization logic of the Snort Detection Engine. An attacker could exploit this vulnerability by sending certain packets through an established connection that is parsed by Snort 3. A successful exploit could allow the attacker to cause a DoS condition when the Snort 3 Detection Engine restarts unexpectedly.

CWE(s)
CWE-667

Related Threats

MITRE ATT&CK Enterprise Techniques

T1499 Endpoint Denial of Service Impact
Adversaries may perform Endpoint Denial of Service (DoS) attacks to degrade or block the availability of services to users.
attack.mitre.org →
T1499.004 Application or System Exploitation Impact
Adversaries may exploit software vulnerabilities that can cause an application or system to crash and deny availability to users.
attack.mitre.org →
T1068 Exploitation for Privilege Escalation Privilege Escalation
Adversaries may exploit software vulnerabilities in an attempt to elevate privileges.
attack.mitre.org →
T1548 Abuse Elevation Control Mechanism Privilege Escalation
Adversaries may circumvent mechanisms designed to control privilege elevation to gain higher-level permissions.
attack.mitre.org →
Derived from this CVE’s CWE(s) via the direct CWE→ATT&CK cross-walk.

CVEs Like This One

CVE-2026-20066Same product: Cisco Secure Firewall Threat Defense
CVE-2026-20058Same product: Cisco Secure Firewall Threat Defense
CVE-2024-20363Same product: Cisco Secure Firewall Threat Defense
CVE-2026-20068Same product: Cisco Secure Firewall Threat Defense
CVE-2026-20054Same product: Cisco Secure Firewall Threat Defense
CVE-2026-20057Same product: Cisco Secure Firewall Threat Defense
CVE-2026-20053Same product: Cisco Secure Firewall Threat Defense
CVE-2026-20067Same product: Cisco Secure Firewall Threat Defense
CVE-2024-20342Same product: Cisco Secure Firewall Threat Defense
CVE-2024-20339Same product: Cisco Secure Firewall Threat Defense

Affected Assets

cisco
snort
3.0.0-233 — 3.6.3.0
cisco
secure firewall threat defense
7.0.0, 7.0.0.1, 7.0.1, 7.0.1.1, 7.0.2
cisco
unified threat defense snort intrusion prevention system engine
17.10.1a, 17.11.1a, 17.12.1a, 17.12.2, 17.12.3

Mitigating Controls

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 mostly match
prevents

Secure SDLC practices directly include code reviews, static analysis, and concurrency standards that prevent improper locking.

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.8.29 Security testing in development and acceptance mostly match
finds

Security testing can detect race conditions and locking errors before release.

A.8.25 Secure development life cycle partial match
prevents

Secure development lifecycle includes concurrency and locking requirements that reduce improper locking defects.

A.8.26 Application security requirements partial match
prevents

Application security requirements can mandate proper lock acquisition/release patterns.

A.8.27 Secure system architecture and engineering principles partial match
prevents

Secure architecture principles address thread-safety and resource synchronization.

A.8.28 Secure coding partial match
prevents

Secure coding standards directly prohibit missing or incorrect lock usage.

A.8.32 Change management partial match
prevents

Change management may catch locking issues introduced by modifications but does not prevent the weakness itself.

References