# CVE-2026-92071: Sandbox escape due to incorrect boundary conditions in the Widget: Win32 component


- **Severity:** Critical 9.6 (`CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:H/I:H/A:H`)
- **Exploited in the wild:** Not known
- **Fix available:** Yes
- **Published:** 15 Sep 2026
- **Updated:** 22 Sep 2026
- **Also known as:** GHSA-5rvr-qj37-q63g, UBUNTU-CVE-2026-92071

## What is CVE-2026-92071?

CVE-2026-92071 is a critical vulnerability in Mozilla Firefox, published on 15 Sep 2026. 

### Official description

Sandbox escape due to incorrect boundary conditions in the Widget: Win32 component. This vulnerability was fixed in Firefox 156, Firefox ESR 153.3, Thunderbird 156, and Thunderbird 153.3.

Weakness: CWE-119 (Improper Restriction of Operations within the Bounds of a Memory Buffer)

## Which versions are affected by CVE-2026-92071?

It affects 2 products.


Products: Mozilla Firefox, Mozilla Thunderbird.

## How do I fix CVE-2026-92071?

Upgrade to a fixed version.

## Is CVE-2026-92071 being exploited?

There is no known exploitation of CVE-2026-92071 in the wild and no public exploit code.

## Other vulnerabilities in Mozilla Firefox

- [CVE-2019-11708](https://insights.sbomify.com/CVE-2019-11708/): Mozilla Firefox and Thunderbird Sandbox Escape (critical 10.0, exploited in the wild)
- [CVE-2010-3765](https://insights.sbomify.com/CVE-2010-3765/): Mozilla Multiple Products Remote Code Execution (critical 9.8, exploited in the wild)
- [CVE-2022-26486](https://insights.sbomify.com/CVE-2022-26486/): Mozilla Firefox Use-After-Free (critical 9.6, exploited in the wild)
- [CVE-2022-26485](https://insights.sbomify.com/CVE-2022-26485/): Mozilla Firefox Use-After-Free (high 8.8, exploited in the wild)
- [CVE-2019-11707](https://insights.sbomify.com/CVE-2019-11707/): Mozilla Firefox and Thunderbird Type Confusion (high 8.8, exploited in the wild)

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2026-92071 and fix it if it is affected.

What it is: CVE-2026-92071 is a critical vulnerability in Mozilla Firefox, published on 15 Sep 2026. 
Exploitation: There is no known exploitation of CVE-2026-92071 in the wild and no public exploit code.

Affected product: Mozilla Firefox. 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-2026-92071/ (Markdown: https://insights.sbomify.com/CVE-2026-92071/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-92071
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-92071
- OSV: https://osv.dev/vulnerability/CVE-2026-92071

---
From sbomify Insights: https://insights.sbomify.com/CVE-2026-92071/
Summaries are generated and may contain mistakes; the official description above is the record.