# CVE-2026-8857: Full RCE using EasyTimeline Extension

> Attackers can achieve full remote code execution via the EasyTimeline extension in Wikimedia timeline software.

- **Severity:** Not scored
- **Exploited in the wild:** Not known
- **Login needed:** Any signed-in user
- **Attackable:** Over the internet
- **Victim action needed:** Not needed
- **Fix available:** Yes
- **Published:** 1 Jul 2026
- **Updated:** 1 Jul 2026
- **Also known as:** GHSA-q6xp-j96f-7vmp, MINI-5q25-vwpj-2f9v, MINI-5v9m-qvmm-969j, MINI-w46q-xr4h-982h

## What is CVE-2026-8857?

CVE-2026-8857 is a code injection vulnerability in Mediawiki Mediawiki, published on 1 Jul 2026. Any signed-in user can exploit it over the network, with no action from the victim.

### Official description

A vulnerability in Wikimedia Foundation timeline.

 This vulnerability is associated with program files scripts/EasyTimeline.Pl, includes/Timeline.Php.

This issue affects timeline: from * before 1.46.0, 1.45.4, 1.44.6, 1.43.9.

Weakness: CWE-94 (Improper Control of Generation of Code)

## Which versions are affected by CVE-2026-8857?

It affects 1 product.


Products: Mediawiki Mediawiki.

## How do I fix CVE-2026-8857?

Upgrade to a fixed version.

## Is CVE-2026-8857 being exploited?

It is not confirmed as exploited in the wild, but public exploit code for CVE-2026-8857 exists.

Public exploit code:

- MediaWiki EasyTimeline - Code Injection RCE (nuclei): http/cves/2026/CVE-2026-8857.yaml

## Other vulnerabilities in Mediawiki Mediawiki

- [CVE-2023-37303](https://insights.sbomify.com/CVE-2023-37303/): Denial of service in n/a (critical 9.8)
- [CVE-2022-29904](https://insights.sbomify.com/CVE-2022-29904/): SQL injection in n/a (critical 9.8)
- [CVE-2022-29906](https://insights.sbomify.com/CVE-2022-29906/): Missing authorization in n/a (critical 9.8)
- [CVE-2022-28205](https://insights.sbomify.com/CVE-2022-28205/): Business logic in n/a (critical 9.8)
- [CVE-2022-28206](https://insights.sbomify.com/CVE-2022-28206/): Missing authorization in n/a (critical 9.8)

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2026-8857 and fix it if it is affected.

What it is: CVE-2026-8857 is a code injection vulnerability in Mediawiki Mediawiki, published on 1 Jul 2026. Any signed-in user can exploit it over the network, with no action from the victim.
Exploitation: It is not confirmed as exploited in the wild, but public exploit code for CVE-2026-8857 exists.

Affected product: Mediawiki Mediawiki. 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-2026-8857/ (Markdown: https://insights.sbomify.com/CVE-2026-8857/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-8857
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-8857
- OSV: https://osv.dev/vulnerability/CVE-2026-8857

---
From sbomify Insights: https://insights.sbomify.com/CVE-2026-8857/
Summaries are generated and may contain mistakes; the official description above is the record.