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Fencer Intel
medium 6.5

CVE-2025-20359 json

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

published last yr. modified 22d ago also EUVD-2025-34665

cvss
6.5
version 3.1, CNA
cisa kev
Not listed
not in CISA's catalog
epss
0.5%
EPSS 0.5% chance of exploitation in 30 days, percentile 41%
public exploits
0
none known

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.

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.

Patch / fix

  • cisco snort 3.9.3.0

Is CVE-2025-20359 in your stack? Fencer shows which of your repositories are affected as soon as an advisory lands, and opens the fix as a pull request.

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CISA SSVC

Exploitation
none
Automatable
yes
Technical impact
partial
Assessed
last yr.

Exploit prediction

0.48% chance of exploitation in the next 30 days, higher than 41% of all scored CVEs (FIRST EPSS, 2026-11-09).

CVSS scores

assigned by version score vector
CNA 3.1 6.5 CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:N/A:L
NVD 3.1 9.1 CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:H

Affected products

  • Cisco Cisco Cyber Vision
  • Cisco Cisco Secure Firewall Threat Defense (FTD) Software
  • Cisco Cisco UTD SNORT IPS Engine Software

Classification

Weakness

References

Sources

Fencer Intel keeps one entry per vulnerability: the CVE id wins, then GHSA, and records that alias each other are merged, except that two CVEs always keep separate entries. The same data is available as JSON.