# CVE-2026-90557 — freeciv

> As of 2026-09-12, CVE-2026-90557 is a MEDIUM-severity vulnerability in freeciv, CVSS v3.1 6.1. No Threadlinqs-tracked threat campaign has been attributed to CVE-2026-90557 as of 2026-09-12; the identifier is re-checked against the Threadlinqs threat corpus on every daily ingest.

**Last updated:** 2026-09-12

## What is CVE-2026-90557?

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.

The record classifies CVE-2026-90557 under weakness class [CWE-125](https://intel.threadlinqs.com/cwe/CWE-125). Its CVSS v3 base vector states that the flaw requires local access to the host, needs no prior authentication, needs a user to take an action first, and has high impact on availability. 1 affected-product entry is recorded, across 1 vendor, listed below. The identifier was first published 23 days ago.

## Severity and exploitation probability

- **CVSS v3.1 base score:** 6.1 — MEDIUM (`CVSS:3.1/AV:L/AC:L/PR:N/UI:R/S:U/C:L/I:N/A:H`)
- **CVSS v4.0 base score:** 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`)
- **CISA KEV:** Not listed in the CISA Known Exploited Vulnerabilities catalog
- **Threadlinqs priority:** 3.1/10 — a Threadlinqs composite of the CVSS base score, the EPSS percentile and public exploit availability
- **Published:** 2026-09-12

## Is CVE-2026-90557 being exploited?

It currently carries a trending score of 30 in the Threadlinqs vulnerability feed.

## Affected products and versions

- **freeciv**: freeciv

## How to fix CVE-2026-90557

No vendor patch reference has been recorded for CVE-2026-90557 in the tracked sources. Follow the references below for a fix, and treat the products listed above as exposed until the vendor states otherwise.

## Threat activity tracking CVE-2026-90557

No threat campaign in the Threadlinqs corpus currently references CVE-2026-90557, in its CVE list or as an indicator. The linkage is recomputed from the live corpus on every daily ingest, so this section fills in as soon as a tracked campaign cites the identifier.

## Sources

Enriched from CVE.org, NVD. Last verified by Threadlinqs on 2026-09-14. This product uses the NVD API but is not endorsed or certified by the NVD.

**Vendor advisory and patch**

- [github.com — patch](https://github.com/freeciv/freeciv/commit/ef0c76c2765fe383140eb1a70dbea1228844152e)
- [github.com — release notes](https://github.com/freeciv/freeciv/releases/tag/R3_2_6)

**Technical analysis**

- [github.com — technical description](https://github.com/freeciv/freeciv/blob/R3_2_5/server/savegame/savegame3.c#L6108)
- [github.com — technical description (savegame2)](https://github.com/freeciv/freeciv/blob/R3_2_5/server/savegame/savegame2.c#L4282)

**Third-party advisory**

- [vulncheck.com — third party advisory](https://www.vulncheck.com/advisories/freeciv-3.1.0-through-3.2.5-out-of-bounds-read-via-savegame)

**Issue tracking and product pages**

- [github.com — product](https://github.com/freeciv/freeciv)
- [redmine.freeciv.org — issue tracking](https://redmine.freeciv.org/issues/2162)

Canonical: https://intel.threadlinqs.com/cve/CVE-2026-90557
Full detection coverage and IOCs for threats exploiting CVE-2026-90557 via the Threadlinqs MCP server (Purple tier): https://intel.threadlinqs.com/mcp