CVE-2025-20359

Multiple Cisco Products Snort 3 MIME Information Disclosure or Denial of Service Vulnerability

CRITICAL

9.1

CVSS Score

Published: October 15, 2025 at 04:17 PM UTC

Updated: October 18, 2026 at 09:10 PM UTC

4 products affected across 1 vendorSnort++Secure Firewall Threat DefenseUnified Threat Defense Snort Intrusion Prevention System Engine

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Severity

CRITICAL9.1

Exploit prediction

EPSS 0.5%

SSVC

No known exploit

Description

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.