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Snort CVE-2026-20058

MEDIUM
Access of Memory Location Before Start of Buffer (CWE-786)
2026-03-04 psirt@cisco.com
5.8
CVSS 3.1 · Vendor: cisco
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Vulnerability Assessment

Weakness
CWE
OWASP Top 10:2025
A06:2021 - Vulnerable and Outdated Components
ASVS 5.0
V15 - Secure Coding and Architecture Buffer access before start
Impact

CVSS 5.8 (MEDIUM). Attack vector: Network. Complexity: Low. Privileges required: None. User interaction: None. Exploitation no authentication required. Exploitable via remote/network.

Exploit ScenarioDerived

A remote attacker without authentication could exploit this vulnerability to cause the Snort 3 Detection Engine to unexpectedly restart, causing a DoS condit.

This Month Plan within 30 days. Why: MEDIUM severity (CVSS 4.0-6.9).
No patch listed yet 0.1% exploitation probability (EPSS)

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AnalysisAIv1 – Mar 12, 2026

Snort 3 Detection Engine crashes when processing malformed VBA data due to improper decompression error handling, allowing unauthenticated remote attackers to trigger denial-of-service conditions across multiple Cisco products. An attacker can exploit this vulnerability by sending crafted VBA payloads to cause unexpected engine restarts without requiring authentication or user interaction. No patch is currently available for this medium-severity flaw.

Earlier versions of this analysis (1)
v1 Mar 12, 2026 - 22:05 CVSS 5.8

Multiple Cisco products are affected by vulnerabilities in the Snort 3 VBA feature that could allow an unauthenticated, remote attacker to cause the Snort 3 Detection Engine to crash. These vulnerabilities are due to improper error checking when decompressing VBA data. [CVSS 5.8 MEDIUM]

RemediationAI

Monitor vendor advisories for a patch. Restrict network access to the affected service where possible.

Affects your stack

Find out whether the stacks and servers you run are on an affected version.

Checking this CVE against your own stacks and servers is part of the Basic plan and up.

Technical ContextAI · show details

Multiple Cisco products are affected by vulnerabilities in the Snort 3 VBA feature that could allow an unauthenticated, remote attacker to cause the Snort 3 Detection Engine to crash.

These vulnerabilities are due to improper error checking when decompressing VBA data. An attacker could exploit these vulnerabilities by sending crafted VBA data to the Snort 3 Detection Engine on the targeted device. A successful exploit could allow the attacker to cause the Snort 3 Detection Engine to unexpect

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Severity by source

Vendor (cisco) PRIMARY 5.8 MEDIUM
AV:N/AC:L/PR:N/UI:N/S:C/C:N/I:N/A:L

Primary rating from Vendor (cisco) · only source for this CVE.

CVSS VectorVendor: cisco

Attack Vector
Network
Attack Complexity
Low
Privileges Required
None
User Interaction
None
Scope
Changed
Confidentiality
None
Integrity
None
Availability
Low

DescriptionCVE.org

Multiple Cisco products are affected by vulnerabilities in the Snort 3 VBA feature that could allow an unauthenticated, remote attacker to cause the Snort 3 Detection Engine to crash.

These vulnerabilities are due to improper error checking when decompressing VBA data. An attacker could exploit these vulnerabilities by sending crafted VBA data to the Snort 3 Detection Engine on the targeted device. A successful exploit could allow the attacker to cause the Snort 3 Detection Engine to unexpectedly restart, causing a DoS condition.

Executive ViewAI

Why It Matters

CVE-2026-20058 presents moderate security risk rated CVSS 5.8. Exploitation could compromise the security of affected deployments. Organizations should apply vendor updates when available and monitor for exploitation.

Business Impact: Low
Compensating Controls

Apply vendor patch. If patching is delayed: restrict network access and enable monitoring.

Threat Intelligence Overview

EPSS Score
0.1%
Top 69% exploitable
Data Quality
4 sources
Confidence: Medium

How this decision was reached

The engine reads each signal below and applies a fixed list of rules from top to bottom. The first rule that matches sets the recommended action – like a statement, every line is shown.

SignalValue
Severity MEDIUM
CISA KEV No
Public POC No
EPSS 0.1%
Patch available No
Active threat No
Deciding rule
MEDIUM severity (CVSS 4.0-6.9)
What every action level means
Emergency Immediate action required. Criteria: CRITICAL + in CISA KEV (actively exploited) without patch, OR CRITICAL + EPSS > 30% without patch, OR CRITICAL + active threat signals without patch.
Act Now Prioritize within 24-48h. Criteria: in KEV with patch available, OR CRITICAL + public POC, OR HIGH + EPSS > 10%, OR CRITICAL + active threat, OR any CRITICAL severity.
This Week Schedule remediation this week. Criteria: HIGH severity (CVSS 7.0-8.9). Patch within normal change window.
This Month Plan within 30 days. Criteria: MEDIUM severity (CVSS 4.0-6.9), lower exploitation probability. Include in regular patch cycle.
Monitor Track and reassess. Criteria: LOW severity (CVSS 0.1-3.9), minimal exploitation risk. No immediate action needed.

SSVC AssessmentENISA

SSVC Decision· derived
Scheduled
Exploitation· derived
None
System Exposure· derived
Open
Automatable· derived
Yes
Human Impact
Low

Priority Score

29
Low Medium High Critical
KEV: 0
EPSS: 0
CVSS: +29
PoC: 0
Weaponized: 0
Threat intel: 0
Gov advisory: 0

Attack Technique

Denial of Service attacks render applications or systems unavailable by overwhelming resources or triggering failure conditions.

Affected Products (CPE)CVE.org

cpe:2.3:a:cisco:snort:*:*:*:*:*:*:*:*
cpe:2.3:a:cisco:secure_firewall_threat_defennse:7.2.0:*:*:*:*:*:*:*
cpe:2.3:a:cisco:secure_firewall_threat_defennse:7.2.0.1:*:*:*:*:*:*:*
cpe:2.3:a:cisco:secure_firewall_threat_defennse:7.2.1:*:*:*:*:*:*:*
cpe:2.3:a:cisco:secure_firewall_threat_defennse:7.2.2:*:*:*:*:*:*:*
cpe:2.3:a:cisco:secure_firewall_threat_defennse:7.2.3:*:*:*:*:*:*:*
cpe:2.3:a:cisco:secure_firewall_threat_defennse:7.2.4:*:*:*:*:*:*:*
cpe:2.3:a:cisco:secure_firewall_threat_defennse:7.2.4.1:*:*:*:*:*:*:*
cpe:2.3:a:cisco:secure_firewall_threat_defennse:7.2.5:*:*:*:*:*:*:*
cpe:2.3:a:cisco:secure_firewall_threat_defennse:7.2.5.1:*:*:*:*:*:*:*
cpe:2.3:a:cisco:secure_firewall_threat_defennse:7.2.5.2:*:*:*:*:*:*:*
cpe:2.3:a:cisco:secure_firewall_threat_defennse:7.2.6:*:*:*:*:*:*:*
cpe:2.3:a:cisco:secure_firewall_threat_defennse:7.2.7:*:*:*:*:*:*:*
cpe:2.3:a:cisco:secure_firewall_threat_defennse:7.2.8:*:*:*:*:*:*:*
cpe:2.3:a:cisco:secure_firewall_threat_defennse:7.2.8.1:*:*:*:*:*:*:*
cpe:2.3:a:cisco:secure_firewall_threat_defennse:7.2.9:*:*:*:*:*:*:*
cpe:2.3:a:cisco:secure_firewall_threat_defennse:7.2.10:*:*:*:*:*:*:*
cpe:2.3:a:cisco:secure_firewall_threat_defennse:7.2.10.2:*:*:*:*:*:*:*
cpe:2.3:a:cisco:secure_firewall_threat_defennse:7.3.0:*:*:*:*:*:*:*
cpe:2.3:a:cisco:secure_firewall_threat_defennse:7.3.1:*:*:*:*:*:*:*
+ 48 more

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