5.8

CVE-2026-20066: cisco cisco secure firewall threat defense (ftd) software Uncontrolled Resource Consumption

CVSS: 5.8v3.1MediumAnalyzed
Published 04-03-2026Last modified 04-03-2026
Open JSON

Vulnerability summary

CVE-2026-20066 is a medium (CVSS 5.8) Uncontrolled Resource Consumption vulnerability in cisco cisco secure firewall threat defense (ftd) software. EPSS estimates a 0.47% chance of exploitation in the next 30 days, higher than 39.4% of scored vulnerabilities.

Overall risk
23/100
0100
Low · default modelHow is this calculated?
CVSS score
5.8/10
010
Medium · v3.1 (CVE.org)
EPSS score
0.47%
0%100%
Low · +0.02 pp in 30 days
KEVNot listedIn no KEV catalog
RansomwareNone recordedNo known use recorded
Public exploits0No public exploits recorded

Timeline

  1. 04-03-2026
    PublishedVulnerability first disclosed.
  2. 04-03-2026
    Last modifiedVulnerability information updated.

Description

Multiple Cisco products are affected by a vulnerability in the Snort 3 Detection Engine that could allow an unauthenticated, remote attacker to cause the Snort 3 Detection Engine to restart, resulting in an interruption of packet inspection. This vulnerability is due to an error in the JSTokenizer normalization logic when the HTTP inspection normalizes JavaScript. 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 cause a DoS condition when the Snort 3 Detection Engine restarts unexpectedly. JSTokenizer is not enabled by default.

CVSS metrics

2 scores · 2 sources · 1 version

EPSS trend

Probability

0.47%

Chance of exploitation in the next 30 days

Percentile

39%

Versus all other CVEs

30-day change

+0.02 pp

From 0.45% on 18-09-2026

18-09-202618-10-2026
EPSS score
0.47%

Known exploited

Compare KEV catalogs

Not in any of the 3 tracked catalogs.

Public exploits

0 found

No public exploits indexed.

Weaknesses

CWE · root cause

Affected systems

Cisco5 products
  • cisco secure firewall threat defense (ftd) software7.4.0 | 7.4.1 | 7.4.1.1 | 7.6.0 | 7.4.2 | 7.4.2.1 | 7.7.0 | 7.4.2.2 | 7.6.1 | 7.4.2.3 | 7.6.2 | 7.7.10 | 7.6.2.1 | 7.7.10.1 | 7.4.2.4 | 7.4.3
  • cisco utd snort ips engine software17.3.1a | 17.2.1r | 17.3.2 | 17.4.1a | 17.5.1 | 17.3.3 | 17.5.1a | 17.3.4 | 17.3.4a | 17.4.2 | 17.4.1b | 17.6.1a | 17.7.1a | 17.6.2 | 17.8.1a | 17.3.5 | 17.6.3 | 17.6.3a | 17.7.2 | 17.9.1a | 17.6.4 | 17.10.1a | 17.3.6 | 17.3.7 | 17.9.2a | 17.6.5 | 17.11.1a | 17.9.3a | 17.12.1a | 17.9.4 | 17.6.6 | 17.3.8 | 17.3.8a | 17.6.6a | 17.9.4a | 17.12.2 | 17.13.1a | 17.9.5a | 17.12.3 | 17.6.7 | 17.14.1a | 17.12.4 | 17.12.3a | 17.15.1a | 17.6.8 | 17.9.6 | 17.6.8a | 17.16.1a | 17.9.5e | 17.12.4a | 17.15.2c | 17.9.5f | 17.12.4b | 17.15.2a | 17.12.5 | 17.17.1 | 17.12.5a | 17.9.7a | 17.15.3a | 17.15.3 | 17.12.5b | 17.12.5c | 17.15.4 | 17.9.7b | 17.18.1 | 17.18.1a | 17.12.6 | 17.9.8 | 17.15.4c | 17.12.5d | 17.18.2
  • secure_firewall_threat_defense7.4.0 | 7.4.1 | 7.4.1.1 | 7.4.2 | 7.4.2.1 | 7.4.2.2 | 7.4.2.3 | 7.4.2.4 | 7.4.3 | 7.6.0 | 7.6.1 | 7.6.2 | 7.6.2.1 | 7.7.0 | 7.7.10 | 7.7.10.1
  • snort≥ 3.0.0-233, < 3.9.7.0
  • unified_threat_defense_snort_intrusion_prevention_system_engine17.2.1r | 17.3.1a | 17.3.2 | 17.3.3 | 17.3.4 | 17.3.4a | 17.3.5 | 17.3.6 | 17.3.7 | 17.3.8 | 17.3.8a | 17.4.1a | 17.4.1b | 17.4.2 | 17.5.1 | 17.5.1a | 17.6.1a | 17.6.2 | 17.6.3 | 17.6.3a | 17.6.4 | 17.6.5 | 17.6.6 | 17.6.6a | 17.6.7 | 17.6.8 | 17.6.8a | 17.7.1a | 17.7.2 | 17.8.1a | 17.9.1a | 17.9.2a | 17.9.3a | 17.9.4 | 17.9.4a | 17.9.5a | 17.9.5e | 17.9.5f | 17.9.6 | 17.9.7a | 17.9.7b | 17.9.8 | 17.10.1a | 17.11.1a | 17.12.1a | 17.12.2 | 17.12.3 | 17.12.3a | 17.12.4 | 17.12.4a | 17.12.4b | 17.12.5 | 17.12.5a | 17.12.5b | 17.12.5c | 17.12.5d | 17.12.6 | 17.13.1a | 17.14.1a | 17.15.1a | 17.15.2a | 17.15.2c | 17.15.3 | 17.15.3a | 17.15.4 | 17.15.4c | 17.16.1a | 17.17.1 | 17.18.1 | 17.18.1a | 17.18.2

1 vendor · 5 products

References

1 links