Secure Firewall Threat DefenseApplication · Cisco
CVE-2022-20751
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 · uneditedA vulnerability in the Snort detection engine integration for Cisco Firepower Threat Defense (FTD) Software could allow an unauthenticated, remote attacker to cause unlimited memory consumption, which could lead to a denial of service (DoS) condition on an affected device. This vulnerability is due to insufficient memory management for certain Snort events. An attacker could exploit this vulnerability by sending a series of crafted IP packets that would generate specific Snort events on an affected device. A sustained attack could cause an out of memory condition on the affected device. A successful exploit could allow the attacker to interrupt all traffic flowing through the affected device. In some circumstances, the attacker may be able to cause the device to reload, resulting in 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 confidenceA vulnerability in Cisco FTD's Snort detection engine allows an unauthenticated remote attacker to cause unlimited memory consumption by sending crafted IP packets that generate specific Snort events. The insufficient memory management for these events can lead to an out-of-memory condition, interrupting all traffic and potentially causing device reload.
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
Secure Firewall Threat DefenseApplication
< 6.4.0.15>= 6.5.0, < 6.6.5.2>= 7.0.0, < 7.0.2= 7.1.0.0CVSS 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
- Unchanged
- Confidentiality
- None
- Integrity
- None
- Availability
- High
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
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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Determine installed Cisco FTD versionRun command 'show version' or 'system version' on the FTD device CLI to retrieve the active software versionAffected if The displayed version falls into any of these ranges: < 6.4.0.15, >= 6.5.0 and < 6.6.5.2, >= 7.0.0 and < 7.0.2, or exactly 7.1.0.0
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Verify Snort detection engine is activeCheck if Snort-based intrusion prevention is enabled via 'show snort statistics' or inspect the intrusion policy configuration in the FTD management interfaceAffected if Snort inspection is enabled and processing traffic on any enabled interface
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Confirm network exposure of management and data interfacesReview interface security zone assignments and access policies to determine if the device accepts external untrusted trafficAffected if The device processes untrusted network traffic from unauthenticated sources with Snort inspection active
The environment is affected if the FTD device runs an affected version listed above AND has Snort intrusion prevention enabled on interfaces exposed to untrusted traffic.
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.
dbcve · scoped6.4.0.156.6.5.27.0.2
Apply the Cisco-provided software update/patch for FTD that addresses the Snort detection engine memory management issue. Implement network-based rate limiting or filtering for suspicious packet patterns as a temporary mitigation while the patch is being deployed.
6.4.0.15, 6.6.5.2, 7.0.2, or any later release (7.2.0+)
- 1. Identify the current FTD version by running 'show version' on the device CLI
- 2. Determine the appropriate upgrade path based on your current major version (6.4.x, 6.5.x-6.6.x, or 7.x)
- 3. Download the fixed FTD software from Cisco (requires valid Cisco service contract)
- 4. Upload the new FTD image to the device using 'copy' command or through Firepower Management Center
- 5. Initiate upgrade using 'upgrade' command or via Firepower Management Center
- 6. Verify the upgrade completed successfully and system is operational
- 7. Confirm the new version is fixed (6.4.0.15+, 6.6.5.2+, 7.0.2+, or 7.2.0+)
Generated from the published advisory — verify against the referenced sources before acting.
Fix this in Secure Firewall Threat Defense
Scoped from the published advisory
- Consultation4.0 h
- Implementation8.0 h
- Testing6.0 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 $5,600.
Scan for this in your stack
Free · runs locallyCheck whether your project pulls in CVE-2022-20751 — 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-2022-20751 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
- No spam, self-promotion, credentials, or personal data