# CVE-2026-20070: Cross-site scripting in Cisco Secure Firewall Adaptive Security Appliance (ASA) Software

> An unauthenticated remote attacker can execute arbitrary script code in a user's browser via a malicious link targeting the VPN web services.

- **Severity:** Medium 6.1 (`CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:L/A:N`)
- **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:** 4 Mar 2026
- **Updated:** 4 Mar 2026
- **Also known as:** GHSA-xwx2-g284-r7j9

## What is CVE-2026-20070?

CVE-2026-20070 is a medium-severity cross-site scripting vulnerability in Cisco Adaptive Security Appliance Software, published on 4 Mar 2026. 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

A vulnerability in the VPN web services component of Cisco Secure Firewall Adaptive Security Appliance (ASA) Software and Cisco Secure Firewall Threat Defense (FTD) Software could allow an unauthenticated, remote attacker to conduct a cross-site scripting (XSS) attack against a browser that is accessing an affected device. 

This vulnerability is due to improper validation of user-supplied input in HTTP requests. An attacker could exploit this vulnerability by persuading a user to follow a link to a malicious website that is designed to submit malicious input to the affected application. A successful exploit could allow the attacker to execute arbitrary HTML or script code in the browser in the context of the VPN web server.

Weakness: CWE-80 (Improper Neutralization of Script-Related HTML Tags in a Web Page)

## Which versions are affected by CVE-2026-20070?

It affects 2 products.


Products: Cisco Adaptive Security Appliance Software, Cisco Secure Firewall Threat Defense.

## How do I fix CVE-2026-20070?

No fix has been published for CVE-2026-20070 yet. Limit exposure of the affected software until one is available.

## Is CVE-2026-20070 being exploited?

There is no known exploitation of CVE-2026-20070 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-2026-20070 and fix it if it is affected.

What it is: CVE-2026-20070 is a medium-severity cross-site scripting vulnerability in Cisco Adaptive Security Appliance Software, published on 4 Mar 2026. 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-2026-20070 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-2026-20070/ (Markdown: https://insights.sbomify.com/CVE-2026-20070/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-20070
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-20070
- OSV: https://osv.dev/vulnerability/CVE-2026-20070

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From sbomify Insights: https://insights.sbomify.com/CVE-2026-20070/
Summaries are generated and may contain mistakes; the official description above is the record.