# CVE-2022-26485: Mozilla Firefox Use-After-Free

> Attackers can exploit a use-after-free flaw in XSLT processing to execute arbitrary code, requiring users to upgrade their browsers.

- **Severity:** High 8.8 (`CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H`)
- **Exploited in the wild:** Yes, since 7 Mar 2022 (CISA KEV)
- **Login needed:** Not needed
- **Attackable:** Over the internet
- **Victim action needed:** A user has to click or open something
- **Fix available:** Yes
- **Published:** 22 Dec 2022
- **Updated:** 21 Oct 2025
- **Also known as:** DEBIAN-CVE-2022-26485, GHSA-rj77-m66j-h24w, UBUNTU-CVE-2022-26485

## What is CVE-2022-26485?

CVE-2022-26485 is a high-severity use after free vulnerability in Mozilla Firefox, published on 22 Dec 2022. 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

Removing an XSLT parameter during processing could have lead to an exploitable use-after-free. We have had reports of attacks in the wild abusing this flaw. This vulnerability affects Firefox < 97.0.2, Firefox ESR < 91.6.1, Firefox for Android < 97.3.0, Thunderbird < 91.6.2, and Focus < 97.3.0.

Weakness: CWE-416 (Use After Free)

## Which versions are affected by CVE-2022-26485?

It affects 4 products.


Products: Mozilla Firefox, Mozilla Firefox Focus, Mozilla Firefox Mobile, Mozilla Thunderbird.

## How do I fix CVE-2022-26485?

Upgrade to a fixed version. US federal agencies must fix it by 21 Mar 2022.

## Is CVE-2022-26485 being exploited?

Yes. Attackers have exploited CVE-2022-26485 in the wild since at least 7 Mar 2022.

Public exploit code:

- https://github.com/mistymntncop/CVE-2022-26485 (github_poc): https://github.com/mistymntncop/CVE-2022-26485

## 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-2019-11707](https://insights.sbomify.com/CVE-2019-11707/): Mozilla Firefox and Thunderbird Type Confusion (high 8.8, exploited in the wild)
- [CVE-2020-6819](https://insights.sbomify.com/CVE-2020-6819/): Mozilla Firefox And Thunderbird Use-After-Free (high 8.1, exploited in the wild)

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2022-26485 and fix it if it is affected.

What it is: CVE-2022-26485 is a high-severity use after free vulnerability in Mozilla Firefox, published on 22 Dec 2022. An attacker can exploit it over the internet without logging in, and only if a user opens a file or follows a link.
Exploitation: Yes. Attackers have exploited CVE-2022-26485 in the wild since at least 7 Mar 2022.

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-2022-26485/ (Markdown: https://insights.sbomify.com/CVE-2022-26485/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2022-26485
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2022-26485
- OSV: https://osv.dev/vulnerability/CVE-2022-26485

---
From sbomify Insights: https://insights.sbomify.com/CVE-2022-26485/
Summaries are generated and may contain mistakes; the official description above is the record.