Mar 18, 2026
View on Steam↗Important Security Updates
3/5 Moderate
Project Zomboid releases critical security patches for Build 41 and 42 to address mod-related vulnerabilities, resulting in the removal of legacy game versions.
Key Changes
- 1Critical security patches released for Build 41 (v41.78.16) and Build 42 (v42.15.2)
- 2Legacy game versions removed from circulation to protect users from unpatched vulnerabilities
- 3Security fixes specifically target vulnerabilities within the modding system
- 4Outdatedunstable branch updated to 42.15.2 and will now lag one version behind Unstable
- 5Potential for minor mod breakage; developers requested to report issues via Discord
- 6Internal security audit completed to identify and resolve complex vulnerabilities
All Changes
🛡️Security(4)
- fixSecurity System: Patched significant security vulnerability reported by community member copiumsawsed.
- fixSecurity System: Resolved additional complex vulnerabilities reported by community member Albion.
- fixSecurity System: Fixed multiple security issues identified during an internal security audit.
- fixModding System: Hardened the modding system against exploits that could affect users through malicious mods.
🎮Game Versions(5)
- changeBuild 41: Updated Default Public Version to 41.78.16.
- changeBuild 42: Updated Unstable branch to 42.15.2.
- changeBuild 42: Updated Outdatedunstable branch to 42.15.2.
- removeLegacy Versions: Removed all legacy versions from official circulation to prevent exposure to unpatched vulnerabilities.
- changeOutdatedunstable: Set Outdatedunstable branch to lag exactly one minor version behind the Unstable branch going forward.
🛠️Modding(2)
- changeMods: Implemented security changes that may cause a small number of existing mods to stop functioning.
- newMod Portal: Opened the #mod_portal Discord channel for developers to report mod breakages caused by the security patch.
Summary
This update focuses on resolving significant security vulnerabilities identified by the modding community and internal audits. While no malicious exploits have been reported, the developers have patched the current stable and unstable branches to ensure user safety. Due to the complexity of these fixes, legacy versions of the game have been removed from circulation, with their future reintroduction currently uncommitted as the team prioritizes Build 42 development.