# CVE-2021-3063: PAN-OS: Denial-of-Service (DoS) Vulnerability in GlobalProtect Portal and Gateway Interfaces

> Unauthenticated attackers can cause a denial of service by sending crafted traffic to GlobalProtect interfaces, restarting the device into maintenance mode.

- **Severity:** High 7.5 (`CVSS:3.1/AV:N/AC:L/PR:N/UI:N/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:** Not needed
- **Fix available:** No
- **Published:** 10 Nov 2021
- **Updated:** 16 Sep 2024
- **Also known as:** GHSA-2h4v-5pj9-9hm9

## What is CVE-2021-3063?

CVE-2021-3063 is a high-severity denial of service vulnerability in Paloaltonetworks Pan-Os, published on 10 Nov 2021. An attacker can exploit it over the internet without logging in, with no action from the victim.

### Official description

An improper handling of exceptional conditions vulnerability exists in Palo Alto Networks GlobalProtect portal and gateway interfaces that enables an unauthenticated network-based attacker to send specifically crafted traffic to a GlobalProtect interface that causes the service to stop responding. Repeated attempts to send this request result in denial of service to all PAN-OS services by restarting the device and putting it into maintenance mode. This issue impacts: PAN-OS 8.1 versions earlier than PAN-OS 8.1.21; PAN-OS 9.0 versions earlier than PAN-OS 9.0.14-h4; PAN-OS 9.1 versions earlier than PAN-OS 9.1.11-h3; PAN-OS 10.0 versions earlier than PAN-OS 10.0.8-h4; PAN-OS 10.1 versions earlier than PAN-OS 10.1.3. Prisma Access customers are not impacted by this issue.

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

## Which versions are affected by CVE-2021-3063?

It affects 1 product.


Products: Paloaltonetworks Pan-Os.

## How do I fix CVE-2021-3063?

No fix has been published for CVE-2021-3063 yet. Limit exposure of the affected software until one is available.

## Is CVE-2021-3063 being exploited?

There is no known exploitation of CVE-2021-3063 in the wild and no public exploit code.

## Other vulnerabilities in Paloaltonetworks Pan-Os

- [CVE-2024-3400](https://insights.sbomify.com/CVE-2024-3400/): Palo Alto Networks PAN-OS Command Injection (critical 10.0, exploited in the wild)
- [CVE-2020-2021](https://insights.sbomify.com/CVE-2020-2021/): Palo Alto Networks PAN-OS Authentication Bypass (critical 10.0, exploited in the wild)
- [CVE-2017-15944](https://insights.sbomify.com/CVE-2017-15944/): Palo Alto Networks PAN-OS Remote Code Execution (critical 9.8, exploited in the wild)
- [CVE-2026-0300](https://insights.sbomify.com/CVE-2026-0300/): Palo Alto Networks PAN-OS Out-of-bounds Write (critical 9.3, exploited in the wild)
- [CVE-2024-0012](https://insights.sbomify.com/CVE-2024-0012/): Palo Alto Networks PAN-OS Management Interface Authentication Bypass (critical 9.3, exploited in the wild)

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2021-3063 and fix it if it is affected.

What it is: CVE-2021-3063 is a high-severity denial of service vulnerability in Paloaltonetworks Pan-Os, published on 10 Nov 2021. 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-2021-3063 in the wild and no public exploit code.

Affected product: Paloaltonetworks Pan-Os. 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-2021-3063/ (Markdown: https://insights.sbomify.com/CVE-2021-3063/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2021-3063
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2021-3063
- OSV: https://osv.dev/vulnerability/CVE-2021-3063

---
From sbomify Insights: https://insights.sbomify.com/CVE-2021-3063/
Summaries are generated and may contain mistakes; the official description above is the record.