CVE-2026-20218: A vulnerability in the Snort 3 Visual Basic for Applications (VBA) Decompression Engine of multiple Cisco prod

Routine

MEDIUM 5.8REMOTE

CVE-2026-20218 is a medium-severity flaw (CVSS 5.8) affecting affected software. Below: why it ranks where it does, which versions are affected, what to do, and the exact commands.

A vulnerability in the Snort 3 Visual Basic for Applications (VBA) Decompression Engine of multiple Cisco products could allow an unauthenticated, remote attacker to cause the Snort 3 Detection Engine to restart unexpectedly, resulting in a denial of service (DoS) condition.   This vulnerability is due to improper range checking when Snort 3 decompresses VBA data, which is user controlled. An attacker could exploit this vulnerability

Why this priority

Remotely exploitable, no login, no user action

A fixed release or distro patch exists.

Risk facts

CVSS score	5.8 (Medium)
Attack vector	Network (remote)
Attack complexity	Low
Privileges needed	None
User interaction	None
EPSS exploit chance	0.4% (top 65%)
CISA exploited list	No
Weakness	CWE-121
Published	2026-10-21
Last modified	2026-10-22

Publisher (CNA): Cisco Systems, Inc.

Timeline

2026-10-21Published CVE record published
2026-10-22 19:17 UTCUpdated Record last modified

Exact fixes by distribution

Fedora 46 · wasmedge · FIXED · 0.18.1-1.fc46 · FEDORA-2026-4c27216e39 · source

sudo dnf upgrade --advisory=FEDORA-2026-4c27216e39

Advisories and coverage

Official advisories

Cisco Security Advisories: Multiple Cisco Products Snort 3 Visual Basic for Applications Buffer Overflow Denial of Service Vulnerability 2026-10-22

Verify at the official source NVD · CVE Program · Report a problem with this page
Scores and fixes here are computed automatically from those and other public sources. Confirm with the vendor advisory before changing production systems.

References

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