Buffer overflow in Freeciv
CVE-2026-90556
Freeciv versions before 3.2.6 contain a heap buffer overflow in worklist_load() when processing savegame files with declared worklist lengths exceeding the fixed array bound of 64 elements. Attackers can craft malicious savegame files that write past the entries array into adjacent heap-allocated struct fields, potentially corrupting memory when a user or server operator loads the file.
Vulnerability class: Buffer Overflow
Published · last modified .
CVSS v3 metric
CVSS v3 base score 7.8 (High). Vector: CVSS:3.1/AV:L/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H.
EPSS exploit prediction
EPSS: 0.002 (10.0th percentile), scored .
Very low probability of exploitation in the next 30 days; routine patching cadence is appropriate. 10th percentile — 10.0% of CVEs in the catalogue have a lower EPSS than this one. How to read EPSS.
EPSS over last 30 days · oldest: 0.002 · newest: 0.002 · change: 0.000
Affected products
Weakness classification (CWE)
References
- github.com/freeciv/freeciv (product)
- github.com/freeciv/freeciv/blob/R3_2_5/server/savegame/savegame2.c (technical-description)
- github.com/freeciv/freeciv/blob/R3_2_5/server/savegame/savegame3.c (technical-description)
- github.com/freeciv/freeciv/commit/75ecde3e86ddf2fe775768450e9a290a4f4d4387 (patch)
- github.com/freeciv/freeciv/releases/tag/R3_2_6 (release-notes)
- redmine.freeciv.org/issues/2161 (issue-tracking)
- www.vulncheck.com/advisories/freeciv-before-3.2.6-heap-buffer-overflow-via-work… (third-party-advisory)
Frequently asked questions
- What is CVE-2026-90556?
- CVE-2026-90556 is a high-severity vulnerability in Freeciv, classified under Heap-based Buffer Overflow. CVSS score: 7.8/10. Published 2026-09-12.
- How severe is CVE-2026-90556?
- High severity. CVSS v3 base score is 7.8 out of 10.