# CVE-2026-107839: ageLANServer: Unbounded JSON Array Allocation in AoE3 Cloud `getFileURL` Endpoint Leads to Remote Denial of Service

> Remote unauthenticated attackers can crash the ageLANServer by sending oversized JSON requests to the getFileURL endpoint, causing service disruption.

- **Severity:** High 7.5 (`CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H`)
- **Exploited in the wild:** Not known
- **Login needed:** Not needed
- **Attackable:** Over the internet
- **Victim action needed:** Not needed
- **Fix available:** Yes
- **Published:** 9 Oct 2026
- **Updated:** 14 Oct 2026
- **Also known as:** GHSA-4jfq-pmq9-257h, GO-2026-6716

## What is CVE-2026-107839?

CVE-2026-107839 is a high-severity denial of service vulnerability in luskaner ageLANServer, published on 9 Oct 2026. An attacker can exploit it over the internet without logging in, with no action from the victim.

### Official description

ageLANServer provides a cross-platform web server and launcher for offline multiplayer in several Age of Empires and Age of Mythology games. Prior to version 1.15.2, the AoE3 POST /game/cloud/getFileURL handler in the bundled game server has no request body size limit or cap on the attacker-controlled JSON names array and allocates response storage directly from the unbounded array length. A remote unauthenticated client can use the default self-registration flow and send an oversized request that causes excessive memory allocation, crashes or hangs the server process, disconnects active players, and keeps the service unavailable until it is restarted. This issue is fixed in version 1.15.2.

Weakness: CWE-400 (Uncontrolled Resource Consumption)

## Which versions are affected by CVE-2026-107839?

3 open source packages ship an affected version, including github.com/luskaner/ageLANServer/server.


| Package | Ecosystem | Affected | Fixed in |
| --- | --- | --- | --- |
| `github.com/luskaner/ageLANServer/server` | Go | All versions | 1.8.2-0.20260809203301-1dd40166a593 |
| `github.com/luskaner/ageLANServer/server` | Go | All versions | 1.8.2-0.20260809203301-1dd40166a593 |
| `github.com/luskaner/ageLANServer/server` | Go | All versions | 1.8.2-0.20260809203301-1dd40166a593 |

## How do I fix CVE-2026-107839?

Upgrade github.com/luskaner/ageLANServer/server to 1.8.2-0.20260809203301-1dd40166a593 or later.

## Is CVE-2026-107839 being exploited?

It is not confirmed as exploited in the wild, but public exploit code for CVE-2026-107839 exists.

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2026-107839 and fix it if it is affected.

What it is: CVE-2026-107839 is a high-severity denial of service vulnerability in luskaner ageLANServer, published on 9 Oct 2026. 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-2026-107839 exists.

Affected packages and fixed versions:
- github.com/luskaner/ageLANServer/server (Go): affected all versions; fixed in 1.8.2-0.20260809203301-1dd40166a593
- github.com/luskaner/ageLANServer/server (Go): affected all versions; fixed in 1.8.2-0.20260809203301-1dd40166a593
- github.com/luskaner/ageLANServer/server (Go): affected all versions; fixed in 1.8.2-0.20260809203301-1dd40166a593

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-2026-107839/ (Markdown: https://insights.sbomify.com/CVE-2026-107839/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-107839
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-107839
- OSV: https://osv.dev/vulnerability/CVE-2026-107839

---
From sbomify Insights: https://insights.sbomify.com/CVE-2026-107839/
Summaries are generated and may contain mistakes; the official description above is the record.