# CVE-2024-1563: Race condition in Focus for iOS

> Attackers can execute unauthorized scripts on top origin sites via a race condition in Firefox Focus for iOS, requiring an upgrade to mitigate.

- **Severity:** High 8.1 (`CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/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:** 22 Feb 2024
- **Updated:** 27 Mar 2025
- **Also known as:** GHSA-783m-f4c2-pgqr

## What is CVE-2024-1563?

CVE-2024-1563 is a high-severity vulnerability in Mozilla Focus for iOS, published on 22 Feb 2024. An attacker can exploit it over the internet without logging in, with no action from the victim.

### Official description

An attacker could have executed unauthorized scripts on top origin sites using a JavaScript URI when opening an external URL with a custom Firefox scheme and a timeout race condition. This vulnerability affects Focus for iOS < 122.

Weakness: CWE-367 (Time-of-check Time-of-use (TOCTOU) Race Condition)

## Which versions are affected by CVE-2024-1563?

It affects 1 product.


Products: Mozilla Firefox Focus.

## How do I fix CVE-2024-1563?

No fix has been published for CVE-2024-1563 yet. Limit exposure of the affected software until one is available.

## Is CVE-2024-1563 being exploited?

There is no known exploitation of CVE-2024-1563 in the wild and no public exploit code.

## Other vulnerabilities in Mozilla Focus for iOS

- [CVE-2024-10474](https://insights.sbomify.com/CVE-2024-10474/): Security feature bypass in Focus for iOS (critical 9.1)
- [CVE-2023-29534](https://insights.sbomify.com/CVE-2023-29534/): Security feature bypass in Firefox for Android (critical 9.1)
- [CVE-2024-0605](https://insights.sbomify.com/CVE-2024-0605/): Race condition in Focus for iOS (high 7.5)
- [CVE-2023-25743](https://insights.sbomify.com/CVE-2023-25743/): Security feature bypass in Firefox (high 7.5)
- [CVE-2025-10290](https://insights.sbomify.com/CVE-2025-10290/): Other in Focus for iOS (medium 6.5)

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2024-1563 and fix it if it is affected.

What it is: CVE-2024-1563 is a high-severity vulnerability in Mozilla Focus for iOS, published on 22 Feb 2024. 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-2024-1563 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-2024-1563/ (Markdown: https://insights.sbomify.com/CVE-2024-1563/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2024-1563
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2024-1563
- OSV: https://osv.dev/vulnerability/CVE-2024-1563

---
From sbomify Insights: https://insights.sbomify.com/CVE-2024-1563/
Summaries are generated and may contain mistakes; the official description above is the record.