---
id: CVE-2025-20359
title: "Multiple Cisco products are affected by a vulnerability in the Snort 3 HTTP Decoder that could allow an unauthenticated, remote attacker to cause the disclosure of possible sensitive data or cause the Snort 3 Detection Engine to crash.\r\n…"
summary: "Multiple Cisco products are affected by a vulnerability in the Snort 3 HTTP Decoder that could allow an unauthenticated, remote attacker to cause the disclosure of possible sensitive data or cause the Snort 3 Detection Engine to crash.\r\n…"
severity: medium
cvss: 6.5
cvssVector: 'CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:N/A:L'
cwe:
  - CWE-127
vendor: cisco
product: snort
affected:
  - 'snort >= 3.0.0-233, < 3.9.3.0'
patched:
  - snort 3.9.3.0
published: '2025-10-15'
updated: '2026-09-17'
sourceUpdated: '2026-09-17T19:25:01.007'
source: NVD
sourceUrl: 'https://nvd.nist.gov/vuln/detail/CVE-2025-20359'
references:
  - url: >-
      https://sec.cloudapps.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-snort3-mime-vulns-tTL8PgVH
    label: psirt@cisco.com
  - url: 'https://software.cisco.com'
tags:
  - nvd
  - csaf
  - vendor-advisory
  - cisco
epss: 0.00481
epssPercentile: 0.41284
ingestedAt: '2026-09-17T19:26:25.279Z'
---

## Overview

Multiple Cisco products are affected by a vulnerability in the Snort 3 HTTP Decoder that could allow an unauthenticated, remote attacker to cause the disclosure of possible sensitive data or cause the Snort 3 Detection Engine to crash.

This vulnerability is due to an error in the logic of buffer handling when the MIME fields of the HTTP header are parsed. This can result in a buffer under-read. 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 induce one of two possible outcomes: the unexpected restarting of the Snort 3 Detection Engine, which could cause a denial of service (DoS) condition, or information disclosure of sensitive information in the Snort 3 data stream. Due to the under-read condition, it is possible that sensitive information that is not valid connection data could be returned.

## Affected

- `snort >= 3.0.0-233, < 3.9.3.0`

## Remediation

Upgrade past the affected range:

- `snort 3.9.3.0`

## Vendor advisories

- **cisco-sa-snort3-mime-vulns-tTL8PgVH** · Cisco · affected: Cisco Firepower 2100 Series, Cisco Firepower 1000 Series, Cisco 3000 Series Industrial Security Appliances (ISA), Cisco Firepower 9000 Series, Cisco Firepower 4100 Series, Cisco Secure Firewall Threat Defense Virtual, … · updated 2026-02-12 · [advisory](https://sec.cloudapps.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-snort3-mime-vulns-tTL8PgVH)