# CVE-2026-90557: Freeciv 3.1.0 through 3.2.5 Out-of-Bounds Read via Savegame

> An attacker can cause a crash or expose heap memory by tricking a user into loading a malicious savegame file in Freeciv.

- **Severity:** Medium 6.9 (`CVSS:4.0/AV:L/AC:L/AT:N/PR:N/UI:P/VC:L/VI:N/VA:H/SC:N/SI:N/SA:N`)
- **Exploited in the wild:** Not known
- **Login needed:** Not needed
- **Attackable:** Local or same network only
- **Victim action needed:** A user has to click or open something
- **Fix available:** Yes
- **Published:** 12 Sep 2026
- **Updated:** 15 Sep 2026
- **Also known as:** DEBIAN-CVE-2026-90557, GHSA-m27m-5mqj-h84f, UBUNTU-CVE-2026-90557

## What is CVE-2026-90557?

CVE-2026-90557 is a medium-severity memory corruption vulnerability in freeciv, published on 12 Sep 2026. It can only be exploited from the same machine or local network, and only if a user opens a file or follows a link.

### Official description

Freeciv versions 3.1.0 through 3.2.5 contain an out-of-bounds read vulnerability in sg_load_player_unit() when processing savegame files with invalid unit activity indices. An attacker can craft a malicious savegame file with an out-of-range activity index that bypasses bounds checking and causes a crash or limited heap memory exposure when loaded.

Weakness: CWE-125 (Out-of-bounds Read)

## Which versions are affected by CVE-2026-90557?


## How do I fix CVE-2026-90557?

Apply the vendor's patch.

## Is CVE-2026-90557 being exploited?

There is no known exploitation of CVE-2026-90557 in the wild and no public exploit code.

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2026-90557 and fix it if it is affected.

What it is: CVE-2026-90557 is a medium-severity memory corruption vulnerability in freeciv, published on 12 Sep 2026. It can only be exploited from the same machine or local network, and only if a user opens a file or follows a link.
Exploitation: There is no known exploitation of CVE-2026-90557 in the wild and no public exploit code.

Affected product: freeciv. 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-2026-90557/ (Markdown: https://insights.sbomify.com/CVE-2026-90557/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-90557
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-90557
- OSV: https://osv.dev/vulnerability/CVE-2026-90557

---
From sbomify Insights: https://insights.sbomify.com/CVE-2026-90557/
Summaries are generated and may contain mistakes; the official description above is the record.