What is the CVSS score of CVE-2026-20066?

CVE-2026-20066 has a CVSS 3.1 base score of 5.8 (Medium). CVSS vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:N/I:N/A:L. EPSS exploitation probability: 0.2%.

Which versions of Cisco are affected by CVE-2026-20066?

CVE-2026-20066 presents moderate security risk, a resource exhaustion vulnerability rated CVSS 5.8. Service availability could be impacted.

How to fix or mitigate CVE-2026-20066?

Within 30 days: Identify affected systems and apply vendor patches as part of regular patch cycle. Monitor vendor channels for patch availability.

Cisco CVE-2026-20066

MEDIUM

Uncontrolled Resource Consumption (CWE-400)

2026-03-04 psirt@cisco.com

Cisco Denial Of Service

5.8

CVSS 3.1 · NVD

Severity by source

NVD PRIMARY

5.8 MEDIUM

AV:N/AC:L/PR:N/UI:N/S:C/C:N/I:N/A:L

Primary rating from NVD · only source for this CVE.

CVSS VectorNVD

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

Attack Vector

Network

Attack Complexity

Low

Privileges Required

None

User Interaction

None

Scope

Changed

Confidentiality

None

Integrity

None

Availability

Low

Lifecycle Timeline

Analysis Generated

Mar 12, 2026 - 22:05 vuln.today

CVE Published

Mar 04, 2026 - 18:16 nvd

MEDIUM 5.8

DescriptionCVE.org

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 due to an error in the JSTokenizer normalization logic when the HTTP inspection normalizes JavaScript. An attacker could exploit this vulnerability by sending crafted HTTP 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. JSTokenizer is not enabled by default.

AnalysisAI

Cisco Snort 3 Detection Engine can be remotely restarted by an unauthenticated attacker through crafted HTTP packets exploiting improper JavaScript normalization in the JSTokenizer logic, causing a denial of service condition that interrupts packet inspection. The vulnerability requires the JSTokenizer feature to be enabled and can be triggered via an established network connection without authentication. No patch is currently available.

Technical ContextAI

Classified as CWE-400 (Uncontrolled Resource Consumption). Affects Snort 3 Detection Engine. 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.