CVE-2026-20067
Denial of Service in Cisco Snort 3 via mDNS Parsing
Publication date: 2026-03-04
Last updated on: 2026-03-04
Assigner: Cisco Systems, Inc.
Description
Description
CVSS Scores
EPSS Scores
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Meta Information
Affected Vendors & Products
| Vendor | Product | Version / Range |
|---|---|---|
| cisco | snort_3 | * |
Helpful Resources
Exploitability
| CWE ID | Description |
|---|---|
| CWE-787 | The product writes data past the end, or before the beginning, of the intended buffer. |
Attack-Flow Graph
AI Powered Q&A
Can you explain this vulnerability to me?
This vulnerability affects multiple Cisco products that use the Snort 3 detection engine. It arises from incomplete error checking when parsing the Multicast DNS fields of the HTTP header. An unauthenticated, remote attacker can exploit this by sending specially crafted HTTP packets through an established connection. This causes the Snort 3 Detection Engine to restart unexpectedly.
The restart of the detection engine results in an interruption of packet inspection, which can lead to a denial of service (DoS) condition.
How can this vulnerability impact me? :
The primary impact of this vulnerability is a denial of service (DoS) condition. An attacker can cause the Snort 3 Detection Engine to restart unexpectedly, interrupting packet inspection.
This interruption can reduce the effectiveness of network security monitoring and intrusion detection, potentially allowing malicious traffic to go undetected during the downtime.
How does this vulnerability affect compliance with common standards and regulations (like GDPR, HIPAA)?:
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How can this vulnerability be detected on my network or system? Can you suggest some commands?
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What immediate steps should I take to mitigate this vulnerability?
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