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SnortApplication · Cisco

CVE-2026-20068

MEDIUM · 5.8 CVSS v3.1 Published 2026-03-04
Fix available
A fix is available. Upgrade to 3.9.2.0 or later.
See remediation →
67/100
Remediation priority · Elevated
Remotely reachable No privileges Zero-click

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 · unedited
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 incomplete error checking when parsing remote procedure call (RPC) data. An attacker could exploit this vulnerability by sending crafted RPC packets through an established connection to be parsed by Snort 3. A successful exploit could allow the attacker to cause a DoS condition when the Snort 3 Detection Engine unexpectedly restarts.

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 confidence

This is a denial-of-service vulnerability in Cisco's Snort 3 detection engine caused by incomplete error handling when parsing malformed Remote Procedure Call (RPC) packets. An unauthenticated remote attacker can send crafted RPC packets through an established connection, triggering an unexpected restart of the Snort 3 detection engine and interrupting packet inspection.

MitigationApply available Cisco security patches for affected products. Until patches are available, consider network-level filtering of suspicious RPC traffic and monitor for unexpected Snort restarts.

Verify against the referenced sources before acting — the references below are authoritative for this CVE, this summary is not.

Affected products & versions What the vendor confirmedThe version ranges the vendor confirmed as vulnerable. If your version sits inside a range here, treat yourself as exposed until you have upgraded.

NVD · CPE data
SnortApplication
Affected:>= 3.0.0-233, < 3.9.2.0
Cyber VisionApplication
Affected:= 3.0.0= 3.0.1= 3.0.2= 3.0.3= 3.0.4= 3.0.5= 3.0.6= 3.1.0= 3.1.1= 3.1.2= 3.2.0= 3.2.1
Secure Firewall Threat DefenseApplication
Affected:= 7.2.4= 7.2.4.1= 7.2.5= 7.2.5.1= 7.2.5.2= 7.2.6= 7.2.7= 7.2.8= 7.2.8.1= 7.2.9= 7.2.10= 7.2.10.2
Unified Threat Defense Snort Intrusion Prevention System EngineOperating system
Affected:= 17.2.1r= 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

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 checks

Work through these to decide whether this CVE applies to you.

  1. Confirm Snort 3 installation and version
    Run 'snort -V' or 'snort3 -V' to display the installed Snort version. Check your package manager for installed snort3 packages.
    Affected if The installed version matches any version reported as affected in Cisco security advisories for this CVE.
  2. Verify RPC protocol inspection is enabled
    Examine the Snort 3 configuration file (typically snort.lua or snort.conf) for 'rpc' or 'rpc_decode' preprocessor settings. Look for 'ips' or 'bindings' rules that enable RPC protocol inspection.
    Affected if RPC protocol inspection is enabled in the Snort 3 configuration, making the parser vulnerable to malformed packets.
  3. Check for unexpected Snort engine restarts
    Review system logs (syslog, /var/log/snort/, or journalctl) for messages indicating snort3 process termination or detection engine restarts without an intentional service restart.
    Affected if Logs show repeated or unexplained Snort 3 detection engine restarts that correlate with RPC traffic processing.
  4. Assess network exposure to RPC traffic
    Determine whether Snort 3 is inspecting traffic on network segments where untrusted or external RPC packets could reach the Snort sensor (especially ports 111, 2049, or other RPC service ports).
    Affected if Snort 3 is deployed to inspect traffic from untrusted networks where an attacker could inject malformed RPC packets.

A user is affected if they run Snort 3 with RPC protocol inspection enabled on a network segment exposed to untrusted traffic, and they observe unexplained detection engine restarts or their version matches the affected range when published.

Generated from the published advisory. Verify against your own configuration.

Check your environment

Paste your version and any relevant configuration and it will be compared against the affected criteria above. Do not include secrets or credentials.

AI-assisted, checked against the advisory. Informational, not a guarantee.

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 data
Upgrade available Upgrade to 3.9.2.0 or later
Fixed in 3.9.2.0
Interim mitigation

Apply available Cisco security patches for affected products. Until patches are available, consider network-level filtering of suspicious RPC traffic and monitor for unexpected Snort restarts.

Fix this in Snort Scoped from the published advisory
  • Consultation4.0 h
  • Implementation8.0 h
  • Testing6.0 h
  • Review / QA2.0 h
20.0 hours of engineering $3,500
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References Go to the primary sourcePrimary sources — vendor advisories, patches and trackers. Where our summary and a reference disagree, the reference wins.

Primary sources

Practitioner notes

Contributed

Peer-ranked notes from engineers who’ve handled CVE-2026-20068 in production — separate from our analysis above.

No notes yet

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What this is

A place for practitioners to share what actually worked: a mitigation you’ve tested, a configuration change, a version- or environment-specific caveat, or a link to a verified patch. The most useful notes rise to the top as peers upvote them, so the signal stays high.

What belongs here
  • 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
  • No spam, self-promotion, credentials, or personal data