CVE-2025-20359
MEDIUMDescription
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.
How to fix
TridentStack Control can deploy fixes like this automatically across your Windows, macOS, and Linux fleet. See how it works
Remediation is compiled from vendor and distribution security advisories. Always confirm against the linked source for your exact version and platform.
CVSS v3 Vector
Exploitability
Impact
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:N/A:L
Exploit Intelligence
Low risk: more likely to be exploited than 36% of all known CVEs.
References
Related Vulnerabilities
Other CWE-127 vulnerabilities, ordered by exploit likelihood. View all
| CVE | Severity | CVSS | EPSS | Exploited | Fix |
|---|---|---|---|---|---|
| CVE-2020-5360 | High | 7.5 | 2.2% | - | Fix |
| CVE-2020-1918 | High | 7.5 | 1.2% | - | Fix |
| CVE-2025-32050 | Medium | 5.9 | 0.8% | - | Fix |
| CVE-2026-5928 | High | 7.5 | 0.4% | - | Fix |
| CVE-2024-25629 | Medium | 4.4 | 0.4% | - | Fix |
| CVE-2024-10395 | High | 8.6 | 0.3% | - | - |
Common questions
How do I fix CVE-2025-20359?
Upgrade snort to 3.9.3.0 or later.
Is CVE-2025-20359 being actively exploited?
Not that we know of. CVE-2025-20359 is not in the CISA Known Exploited Vulnerabilities catalog. Its EPSS score of 0.42% is the estimated probability that it will be exploited in the next 30 days. That is higher than 36% of all scored CVEs.
How severe is CVE-2025-20359?
CVE-2025-20359 has a CVSS v3 base score of 6.5, rated medium. CVSS rates the technical impact if the vulnerability is exploited, not how likely that is, so weigh it alongside the exploit-prediction score when you decide what to patch first.
What does CVE-2025-20359 affect?
Published advisories record a fix for snort (NVD). Only products with a sourced advisory are listed, so treat this as what we can cite rather than a complete inventory.
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Markdown
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This product uses NVD data but is not endorsed or certified by the NVD. EPSS scores courtesy of FIRST.org (https://www.first.org/epss). Source: CISA KEV Catalog. Data as of 2026-09-17.