# CVE-2019-1951: Cisco SD-WAN Solution Packet Filtering Bypass Vulnerability

> Unauthenticated remote attackers can bypass L3 and L4 traffic filters to inject arbitrary packets into the network.

- **Severity:** Medium 5.8 (`CVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:C/C:N/I:L/A:N`)
- **Exploited in the wild:** Not known
- **Login needed:** Not needed
- **Attackable:** Over the internet
- **Victim action needed:** Not needed
- **Fix available:** No
- **Published:** 8 Aug 2019
- **Updated:** 19 Nov 2024
- **Also known as:** GHSA-xpmg-vx7g-292w

## What is CVE-2019-1951?

CVE-2019-1951 is a medium-severity vulnerability in Cisco SD-WAN Solution, published on 8 Aug 2019. An attacker can exploit it over the internet without logging in, with no action from the victim.

### Official description

A vulnerability in the packet filtering features of Cisco SD-WAN Solution could allow an unauthenticated, remote attacker to bypass L3 and L4 traffic filters. The vulnerability is due to improper traffic filtering conditions on an affected device. An attacker could exploit this vulnerability by crafting a malicious TCP packet with specific characteristics and sending it to a target device. A successful exploit could allow the attacker to bypass the L3 and L4 traffic filters and inject an arbitrary packet in the network.

Weakness: CWE-20 (Improper Input Validation)

## Which versions are affected by CVE-2019-1951?

It affects 1 product.


Products: Cisco Sd-Wan Firmware.

## How do I fix CVE-2019-1951?

No fix has been published for CVE-2019-1951 yet. Limit exposure of the affected software until one is available.

## Is CVE-2019-1951 being exploited?

There is no known exploitation of CVE-2019-1951 in the wild and no public exploit code.

## Other vulnerabilities in Cisco SD-WAN Solution

- [CVE-2020-3381](https://insights.sbomify.com/CVE-2020-3381/): Cisco SD-WAN vManage Software Directory Traversal Vulnerability (high 8.8)
- [CVE-2020-3115](https://insights.sbomify.com/CVE-2020-3115/): Cisco SD-WAN Solution Local Privilege Escalation Vulnerability (high 8.8)
- [CVE-2019-1626](https://insights.sbomify.com/CVE-2019-1626/): Cisco SD-WAN Solution Privilege Escalation Vulnerability (high 8.8)
- [CVE-2020-3351](https://insights.sbomify.com/CVE-2020-3351/): Cisco SD-WAN Solution Software Denial of Service Vulnerability (high 8.6)
- [CVE-2020-3369](https://insights.sbomify.com/CVE-2020-3369/): Cisco SD-WAN vEdge Routers Denial of Service Vulnerability (high 8.6)

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2019-1951 and fix it if it is affected.

What it is: CVE-2019-1951 is a medium-severity vulnerability in Cisco SD-WAN Solution, published on 8 Aug 2019. 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-2019-1951 in the wild and no public exploit code.

Affected product: Cisco SD-WAN Solution. 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-2019-1951/ (Markdown: https://insights.sbomify.com/CVE-2019-1951/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2019-1951
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2019-1951
- OSV: https://osv.dev/vulnerability/CVE-2019-1951

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From sbomify Insights: https://insights.sbomify.com/CVE-2019-1951/
Summaries are generated and may contain mistakes; the official description above is the record.