CVE-2026-20054
Official description Straight from the sourceThe vendor's or NVD's own wording, published unedited. Authoritative, but often terse — it says what broke, rarely what to do.
NVD · uneditedMultiple Cisco products are affected by a vulnerability in the Snort 3 VBA feature that could allow an unauthenticated, remote attacker to cause the Snort 3 Detection Engine to crash. This vulnerability is due to improper error checking when decompressing VBA data. An attacker could exploit this vulnerability 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 enter an infinite loop, causing a DoS condition.
Technical summary Written by usOur analysis, written from the advisory, the CVSS vector and the affected-version data. It adds context the advisory leaves out, and never invents facts that are not in the source.
dbcve analysis · high confidenceThis is a denial of service vulnerability in Snort 3's VBA (Visual Basic for Applications) detection feature. The vulnerability stems from improper error checking during VBA data decompression, allowing an unauthenticated remote attacker to send crafted VBA data that causes the Snort 3 Detection Engine to enter an infinite loop.
Verify against the referenced sources before acting — the references below are authoritative for this CVE, this summary is not.
CVSS breakdown How the score is builtThe industry scoring standard. It rates how the flaw is reached, what it takes to exploit, and what an attacker gains — the score is derived from those, not the other way round.
From the vector- Attack vector
- Network
- Complexity
- Low
- Privileges
- None
- User interaction
- None
- Scope
- Changed
- Confidentiality
- None
- Integrity
- None
- Availability
- Low
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:N/I:N/A:L
Am I affected? How to checkSteps we derive from the advisory and the affected-version data, so you can decide whether this CVE reaches your setup. They are a guide, not a scan — your own configuration is the authority.
dbcve checksWork through these to decide whether this CVE applies to you.
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Confirm Snort 3 installationRun 'snort3 --version' or check for snort3 binary presence in /usr/local/bin/snort3, /usr/sbin/snort3, or similar pathsAffected if Snort 3 is not installed on the system
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Identify Snort 3 versionExecute 'snort3 --version' and note the full version string; compare against any known affected version ranges from Cisco advisoriesAffected if The installed version falls within the affected range and VBA inspection is enabled
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Locate Snort 3 configuration fileFind snort.lua or snort.conf in /etc/snort/, /usr/local/etc/snort/, or the directory specified via --config option at startupAffected if No configuration file is found - unable to verify VBA inspection status
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Check if VBA inspection is enabledSearch the snort.lua or snort.conf file for 'vba' or 'vbcript' or 'visual_basic' inspection module settings; also check for related preprocessor rules like 'inspect_vba' or 'vba_inspect'Affected if VBA/VBscript inspection is explicitly enabled in the configuration (vba_inspect or similar module is loaded and active)
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Verify activeBindings or policy configurationCheck if the policy that loads the VBA inspection module is referenced in the activeBindings list in snort.lua, or if the --lua-script arguments at runtime include VBA-related scriptsAffected if The VBA inspection module is bound to an active inspection policy
The environment is affected only if Snort 3 is installed with a vulnerable version AND VBA/VBscript inspection is explicitly enabled in the Snort configuration or runtime parameters.
Generated from the published advisory. Verify against your own configuration.
Remediation Closing itWhat it takes to close this. Where a vendor fix exists we point at it; where none exists we say so plainly, and can build one. Effort estimates are scoped from the advisory, not from your codebase.
From vendor dataApply vendor patches from Cisco for affected products. Consider disabling VBA inspection in Snort 3 if not required, or implement network-level filtering to block suspicious VBA content until patches are available.
- Consultation4.0 h
- Implementation6.0 h
- Testing4.0 h
- Review / QA2.0 h
An estimate, not a bill — we confirm scope with you before any work starts. Need it this week? Rush from $4,544.
Scan for this in your stack
Free · runs locallyCheck whether your project pulls in CVE-2026-20054 — or any other known-vulnerable package — straight from your lock files. Free and open source; it runs locally and uploads nothing.
References Go to the primary sourcePrimary sources — vendor advisories, patches and trackers. Where our summary and a reference disagree, the reference wins.
Primary sourcesPractitioner notes
ContributedPeer-ranked notes from engineers who’ve handled CVE-2026-20054 in production — separate from our analysis above.
The advisory tells you what broke. It rarely tells you what actually worked. If you’ve dealt with this one, that detail is what the next engineer is searching for.
- The version that genuinely resolved it — not the one the vendor claimed
- A config change or rule that shut the vector down
- A gotcha in the upgrade path that cost you an afternoon
No notes yet
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- Verified mitigations, workarounds, and config changes
- Version or environment caveats, and links to real fixes
- No weaponised exploit code, or anything meant to cause harm
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