# CVE-2020-1645: Junos OS: MX Series: Services card might restart when DNS filtering is enabled

> An attacker can crash the services card via packet streams, causing a restart that temporarily bypasses DNS filtering security controls.

- **Severity:** High 8.3 (`CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:L/I:L/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:** 17 Jul 2020
- **Updated:** 16 Sep 2024
- **Also known as:** GHSA-cvr9-hv4p-wfcw

## What is CVE-2020-1645?

CVE-2020-1645 is a high-severity vulnerability in Juniper Junos, published on 17 Jul 2020. An attacker can exploit it over the internet without logging in, with no action from the victim.

### Official description

When DNS filtering is enabled on Juniper Networks Junos MX Series with one of the following cards MS-PIC, MS-MIC or MS-MPC, an incoming stream of packets processed by the Multiservices PIC Management Daemon (mspmand) process, responsible for managing "URL Filtering service", may crash, causing the Services PIC to restart. While the Services PIC is restarting, all PIC services including DNS filtering service (DNS sink holing) will be bypassed until the Services PIC completes its boot process. If the issue occurs, system core-dumps output will show a crash of mspmand process: root@device> show system core-dumps -rw-rw---- 1 nobody wheel 575685123 <Date> /var/tmp/pics/mspmand.core.<*>.gz This issue affects Juniper Networks Junos OS: 17.3 versions prior to 17.3R3-S8; 18.3 versions prior to 18.3R2-S4, 18.3R3-S1; 18.4 versions prior to 18.4R2-S5, 18.4R3; 19.1 versions prior to 19.1R2-S2, 19.1R3; 19.2 versions prior to 19.2R1-S5, 19.2R2; 19.3 versions prior to 19.3R2-S3, 19.3R3; 19.4 versions prior to 19.4R1-S3, 19.4R2. This issue does not affect Juniper Networks Junos OS releases prior to 17.3R2.

Weakness: CWE-362 (Concurrent Execution using Shared Resource with Improper Synchronization)

## Which versions are affected by CVE-2020-1645?

It affects 1 product.


Products: Juniper Junos.

## How do I fix CVE-2020-1645?

No fix has been published for CVE-2020-1645 yet. Limit exposure of the affected software until one is available.

## Is CVE-2020-1645 being exploited?

There is no known exploitation of CVE-2020-1645 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-2020-1645 and fix it if it is affected.

What it is: CVE-2020-1645 is a high-severity vulnerability in Juniper Junos, published on 17 Jul 2020. 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-2020-1645 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-2020-1645/ (Markdown: https://insights.sbomify.com/CVE-2020-1645/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2020-1645
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2020-1645
- OSV: https://osv.dev/vulnerability/CVE-2020-1645

---
From sbomify Insights: https://insights.sbomify.com/CVE-2020-1645/
Summaries are generated and may contain mistakes; the official description above is the record.