# CVE-2026-11799: UXSS in Focus for iOS / Klar Webkit navigation

> An attacker can execute arbitrary scripts in the context of the Focus or Klar iOS browser, potentially compromising user sessions and data.

- **Severity:** High 7.5 (`CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/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:** 9 Jun 2026
- **Updated:** 10 Jun 2026
- **Also known as:** GHSA-2j9g-whc6-7j55

## What is CVE-2026-11799?

CVE-2026-11799 is a high-severity cross-site scripting vulnerability in Mozilla Focus for iOS, published on 9 Jun 2026. An attacker can exploit it over the internet without logging in, with no action from the victim.

### Official description

UXSS in Focus for iOS / Klar Webkit navigation. This vulnerability was fixed in Focus for iOS 151.3.1 and Klar for iOS 151.3.1.

Weakness: CWE-79 (Improper Neutralization of Input During Web Page Generation)

## Which versions are affected by CVE-2026-11799?

It affects 2 products.


Products: Mozilla Focus, Mozilla Klar.

## How do I fix CVE-2026-11799?

No fix has been published for CVE-2026-11799 yet. Limit exposure of the affected software until one is available.

## Is CVE-2026-11799 being exploited?

There is no known exploitation of CVE-2026-11799 in the wild and no public exploit code.

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2026-11799 and fix it if it is affected.

What it is: CVE-2026-11799 is a high-severity cross-site scripting vulnerability in Mozilla Focus for iOS, published on 9 Jun 2026. 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-2026-11799 in the wild and no public exploit code.

Affected product: Mozilla Focus for iOS. 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-2026-11799/ (Markdown: https://insights.sbomify.com/CVE-2026-11799/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-11799
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-11799
- OSV: https://osv.dev/vulnerability/CVE-2026-11799

---
From sbomify Insights: https://insights.sbomify.com/CVE-2026-11799/
Summaries are generated and may contain mistakes; the official description above is the record.