What’s Vulnerable › Vulnerabilities

CVE-2026-90556: Freeciv before 3.2.6 Heap Buffer Overflow via worklist_load

• Severity: high (CVSS 7.8 v3.1)
• Exploited in the wild: not listed in CISA KEV
• EPSS: 0.2% probability of exploitation in the next 30 days
• Public exploit or detection template: none known
• Published: 2026-09-12 · updated 2026-09-23
• Weakness: CWE-122

Description

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.

Affected products

• freeciv: before 3.2.6 — fixed in 3.2.6

How to fix

Upgrade to a fixed version: freeciv 3.2.6. Check the vendor advisory for mitigations.

References

• https://github.com/freeciv/freeciv
• https://github.com/freeciv/freeciv/blob/R3_2_5/server/savegame/savegame2.c#L788
• https://github.com/freeciv/freeciv/blob/R3_2_5/server/savegame/savegame3.c#L964
• https://github.com/freeciv/freeciv/commit/75ecde3e86ddf2fe775768450e9a290a4f4d4387
• https://github.com/freeciv/freeciv/releases/tag/R3_2_6
• https://redmine.freeciv.org/issues/2161
• https://www.vulncheck.com/advisories/freeciv-before-3.2.6-heap-buffer-overflow-via-worklist-load

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