# CVE-2017-3793: Denial of service in Cisco ASA Software and Cisco FTD Software

> Remote attackers can cause a denial of service on Cisco ASA and FTD devices by exhausting the TCP out-of-order queue, dropping all incoming traffic.

- **Severity:** Medium 4.0 (`CVSS:3.0/AV:N/AC:H/PR:N/UI:N/S:C/C:N/I:N/A:L`)
- **Exploited in the wild:** Not known
- **Login needed:** Not needed
- **Attackable:** Over the internet
- **Victim action needed:** Not needed
- **Fix available:** No
- **Published:** 20 Apr 2017
- **Updated:** 5 Aug 2024
- **Also known as:** GHSA-4p4v-vxhg-4mmr

## What is CVE-2017-3793?

CVE-2017-3793 is a medium-severity denial of service vulnerability in Cisco Adaptive Security Appliance Software, published on 20 Apr 2017. An attacker can exploit it over the internet without logging in, with no action from the victim.

### Official description

A vulnerability in the TCP normalizer of Cisco Adaptive Security Appliance (ASA) Software (8.0 through 8.7 and 9.0 through 9.6) and Cisco Firepower Threat Defense (FTD) Software could allow an unauthenticated, remote attacker to cause Cisco ASA and FTD to drop any further incoming traffic on all interfaces, resulting in a denial of service (DoS) condition. The vulnerability is due to improper limitation of the global out-of-order TCP queue for specific block sizes. An attacker could exploit this vulnerability by sending a large number of unique permitted TCP connections with out-of-order segments. An exploit could allow the attacker to exhaust available blocks in the global out-of-order TCP queue, causing the dropping of any further incoming traffic on all interfaces and resulting in a DoS condition. Cisco Bug IDs: CSCvb46321.

Weakness: CWE-400 (Uncontrolled Resource Consumption), CWE-399

## Which versions are affected by CVE-2017-3793?

It affects 1 product.


Products: Cisco Adaptive Security Appliance Software.

## How do I fix CVE-2017-3793?

No fix has been published for CVE-2017-3793 yet. Limit exposure of the affected software until one is available.

## Is CVE-2017-3793 being exploited?

There is no known exploitation of CVE-2017-3793 in the wild and no public exploit code.

## Other vulnerabilities in Cisco Adaptive Security Appliance Software

- [CVE-2025-20333](https://insights.sbomify.com/CVE-2025-20333/): Cisco Secure Firewall Adaptive Security Appliance (ASA) and Secure Firewall Threat Defense (FTD) Buffer Overflow (critical 9.9, exploited in the wild)
- [CVE-2016-6366](https://insights.sbomify.com/CVE-2016-6366/): Cisco Adaptive Security Appliance (ASA) SNMP Buffer Overflow (high 8.8, exploited in the wild)
- [CVE-2026-20349](https://insights.sbomify.com/CVE-2026-20349/): Cisco Secure Firewall Adaptive Security Appliance (ASA) and Secure Firewall Threat Defense (FTD) Heap Inspection (high 8.6, exploited in the wild)
- [CVE-2024-20353](https://insights.sbomify.com/CVE-2024-20353/): Cisco ASA and FTD Denial of Service (high 8.6, exploited in the wild)
- [CVE-2016-6367](https://insights.sbomify.com/CVE-2016-6367/): Cisco Adaptive Security Appliance (ASA) CLI Remote Code Execution (high 7.8, exploited in the wild)

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2017-3793 and fix it if it is affected.

What it is: CVE-2017-3793 is a medium-severity denial of service vulnerability in Cisco Adaptive Security Appliance Software, published on 20 Apr 2017. An attacker can exploit it over the internet without logging in, with no action from the victim.
Exploitation: There is no known exploitation of CVE-2017-3793 in the wild and no public exploit code.

Affected product: Cisco Adaptive Security Appliance Software. No package-level version data is available, so check the vendor advisory linked from the reference page.

Task:
1. Search the dependency manifests and lockfiles (for example package.json, package-lock.json, requirements.txt, poetry.lock, uv.lock, pom.xml, build.gradle, go.mod, Cargo.lock, Gemfile.lock) and any Dockerfiles for the affected packages, including transitive dependencies.
2. If an affected version is in use, upgrade it to the fixed version for its release line with the project's package manager, so the lockfile is regenerated. Prefer the smallest upgrade that fixes it.
3. If there is no fix, or the upgrade would break the build, do not guess: explain the risk and the safest workaround instead.
4. Run the tests and summarise what changed and why.
5. If nothing in the project is affected, say so and change nothing.

Reference: https://insights.sbomify.com/CVE-2017-3793/ (Markdown: https://insights.sbomify.com/CVE-2017-3793/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2017-3793
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2017-3793
- OSV: https://osv.dev/vulnerability/CVE-2017-3793

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From sbomify Insights: https://insights.sbomify.com/CVE-2017-3793/
Summaries are generated and may contain mistakes; the official description above is the record.