What’s Vulnerable › Vulnerabilities
CVE-2025-20359: Multiple Cisco Products Snort 3 MIME Information Disclosure or Denial of Service Vulnerability
- Severity: critical (CVSS 9.1 v3.1)
- Exploited in the wild: not listed in CISA KEV
- EPSS: 0.5% probability of exploitation in the next 30 days
- Public exploit or detection template: none known
- Published: 2025-10-15 · updated 2026-10-18
- Weakness: CWE-127
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.
Affected products
- Cisco Snort: from 3.0.0-233 before 3.9.3.0 — fixed in 3.9.3.0
How to fix
Upgrade to a fixed version: Cisco Snort 3.9.3.0. Check the vendor advisory for mitigations.
References
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