---
id: "CVE-2026-20356"
kind: "vulnerability"
aliases: ["CVE-2026-20356"]
title: "Snort 3: multiple uncontrolled resource consumption flaws found in review"
severity: "high"
cvss: 7.5
epss: 0.00346
exploited: false
status: "open"
category: "infrastructure"
products: []
ecosystems: []
tags: ["cisco", "infrastructure", "network-security", "snort"]
not_affected_if: []
published_at: "2026-10-21T17:18:28+00:00"
first_seen_at: "2026-10-23T21:57:29+00:00"
updated_at: "2026-10-25T03:16:33+00:00"
sources: [{"source": "nvd", "url": "https://nvd.nist.gov/vuln/detail/CVE-2026-20356", "first_seen_at": "2026-10-23T21:57:29+00:00"}, {"source": "epss", "url": "https://api.first.org/data/v1/epss?cve=CVE-2026-20356", "first_seen_at": "2026-10-24T13:15:54+00:00"}]
---

# Snort 3: multiple uncontrolled resource consumption flaws found in review

Cisco's internal review of Open Source Snort 3 found several flaws that consume resources without limit (CWE-400), fixed in hardening releases. The sources do not say what triggers them or what an attacker gets beyond resource exhaustion.

_Summary, check and fix written by a model from the sources; labelled as such._

## How to check

- unknown

## Fix

- Move Snort 3 to a hardened release from Cisco's advisory; the exact fixed version is not in the sources

## Timeline

- 2026-10-23T21:57:29+00:00 nvd https://nvd.nist.gov/vuln/detail/CVE-2026-20356
- 2026-10-24T13:15:54+00:00 epss https://api.first.org/data/v1/epss?cve=CVE-2026-20356

## From the sources

As part of Cisco's ongoing commitment to proactive security and product quality, the Cisco owned Open Source Snort 3 Software engineering team has conducted a comprehensive internal security review. This review resulted in software hardening releases that address multiple internally discovered vulnerabilities.

The vulnerabilities tracked by CVE-2026-20356 are related to issues concerning uncontrolled resource consumption that are grouped under the Common Weakness Enumeration (CWE) Base CWE-400.

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_Free to read at a human pace. An API with keys and an MCP server are in preparation; early access: hello@infrastack.ai_