# CVE-2022-34477: Information disclosure in Firefox

> Firefox leaked cross-origin resource information via MediaError messages, enabling XS-Leaks attacks against same-site resources.

- **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:** Yes
- **Published:** 22 Dec 2022
- **Updated:** 15 Apr 2025
- **Also known as:** GHSA-hc2g-x3vc-qhj4, UBUNTU-CVE-2022-34477

## What is CVE-2022-34477?

CVE-2022-34477 is a high-severity vulnerability in Mozilla Firefox, published on 22 Dec 2022. An attacker can exploit it over the internet without logging in, with no action from the victim.

### Official description

The MediaError message property should be consistent to avoid leaking information about cross-origin resources; however for a same-site cross-origin resource, the message could have leaked information enabling XS-Leaks attacks. This vulnerability affects Firefox < 102.

Weakness: CWE-203 (Observable Discrepancy)

## Which versions are affected by CVE-2022-34477?

It affects 1 product.


Products: Mozilla Firefox.

## How do I fix CVE-2022-34477?

Upgrade to a fixed version.

## Is CVE-2022-34477 being exploited?

It is not confirmed as exploited in the wild, but public exploit code for CVE-2022-34477 exists.

## 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-2022-34477 and fix it if it is affected.

What it is: CVE-2022-34477 is a high-severity vulnerability in Mozilla Firefox, published on 22 Dec 2022. An attacker can exploit it over the internet without logging in, with no action from the victim.
Exploitation: It is not confirmed as exploited in the wild, but public exploit code for CVE-2022-34477 exists.

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-2022-34477/ (Markdown: https://insights.sbomify.com/CVE-2022-34477/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2022-34477
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2022-34477
- OSV: https://osv.dev/vulnerability/CVE-2022-34477

---
From sbomify Insights: https://insights.sbomify.com/CVE-2022-34477/
Summaries are generated and may contain mistakes; the official description above is the record.