# CVE-2019-0051: SRX5000 Series: Denial of Service vulnerability in SSL-Proxy feature.

> Remote attackers can crash the flowd daemon on Juniper SRX devices via malicious SSL/TLS servers, causing extended denial of service.

- **Severity:** Medium 6.5 (`CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:N/I:N/A:H`)
- **Exploited in the wild:** Not known
- **Login needed:** Not needed
- **Attackable:** Over the internet
- **Victim action needed:** A user has to click or open something
- **Fix available:** No
- **Published:** 9 Oct 2019
- **Updated:** 16 Sep 2024
- **Also known as:** GHSA-prp9-q697-6cf2

## What is CVE-2019-0051?

CVE-2019-0051 is a medium-severity denial of service vulnerability in Juniper Junos, published on 9 Oct 2019. An attacker can exploit it over the internet without logging in, and only if a user opens a file or follows a link.

### Official description

SSL-Proxy feature on SRX devices fails to handle a hardware resource limitation which can be exploited by remote SSL/TLS servers to crash the flowd daemon. Repeated crashes of the flowd daemon can result in an extended denial of service condition. For this issue to occur, clients protected by the SRX device must initiate a connection to the malicious server. This issue affects: Juniper Networks Junos OS on SRX5000 Series: 12.3X48 versions prior to 12.3X48-D85; 15.1X49 versions prior to 15.1X49-D180; 17.3 versions prior to 17.3R3-S7; 17.4 versions prior to 17.4R2-S6, 17.4R3; 18.1 versions prior to 18.1R3-S8; 18.2 versions prior to 18.2R3; 18.3 versions prior to 18.3R2; 18.4 versions prior to 18.4R2; 19.1 versions prior to 19.1R2.

Weakness: CWE-755 (Improper Handling of Exceptional Conditions)

## Which versions are affected by CVE-2019-0051?

It affects 1 product.


Products: Juniper Junos.

## How do I fix CVE-2019-0051?

No fix has been published for CVE-2019-0051 yet. Limit exposure of the affected software until one is available.

## Is CVE-2019-0051 being exploited?

There is no known exploitation of CVE-2019-0051 in the wild and no public exploit code.

## Other vulnerabilities in Juniper Junos

- [CVE-2023-36845](https://insights.sbomify.com/CVE-2023-36845/): Juniper Junos OS EX Series and SRX Series PHP External Variable Modification (critical 9.8, exploited in the wild)
- [CVE-2020-1631](https://insights.sbomify.com/CVE-2020-1631/): Juniper Junos OS Path Traversal (high 8.8, exploited in the wild)
- [CVE-2025-21590](https://insights.sbomify.com/CVE-2025-21590/): Juniper Junos OS Improper Isolation or Compartmentalization (medium 6.7, exploited in the wild)
- [CVE-2023-36851](https://insights.sbomify.com/CVE-2023-36851/): Juniper Junos OS SRX Series Missing Authentication for Critical Function (medium 5.3, exploited in the wild)
- [CVE-2023-36844](https://insights.sbomify.com/CVE-2023-36844/): Juniper Junos OS EX Series PHP External Variable Modification (medium 5.3, exploited in the wild)

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2019-0051 and fix it if it is affected.

What it is: CVE-2019-0051 is a medium-severity denial of service vulnerability in Juniper Junos, published on 9 Oct 2019. An attacker can exploit it over the internet without logging in, and only if a user opens a file or follows a link.
Exploitation: There is no known exploitation of CVE-2019-0051 in the wild and no public exploit code.

Affected product: Juniper Junos. 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-2019-0051/ (Markdown: https://insights.sbomify.com/CVE-2019-0051/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2019-0051
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2019-0051
- OSV: https://osv.dev/vulnerability/CVE-2019-0051

---
From sbomify Insights: https://insights.sbomify.com/CVE-2019-0051/
Summaries are generated and may contain mistakes; the official description above is the record.