CVE-2016-5237 Valvesoftware CVE debrief

Who should care

Administrators and security teams responsible for systems running Valve Steam or SteamOS 3.42.16.13, especially endpoints where non-admin local users may be able to reach the Steam installation directory.

Technical summary

NVD classifies the issue as CWE-264 and lists a CVSS v3.0 vector of AV:L/AC:L/PR:L/UI:R/S:U/C:L/I:L/A:L. The core problem is overly permissive file access in the Steam program directory, which allows a local user to alter program files and potentially influence privilege-sensitive execution. NVD’s vulnerable CPE scope points to SteamOS through version 3.42.16.13, and the record includes third-party references describing the local privilege-escalation impact.

Defensive priority

Medium. The attack requires local access and user interaction, but the impact can include privilege escalation through tampering with installed program files.

Recommended defensive actions

• Audit the Steam program directory permissions and confirm that unprivileged local users cannot write to application binaries or supporting files.
• Remove any unnecessary write access from shared or low-privilege accounts and verify directory ACLs after software installation or updates.
• Apply vendor updates or configuration changes that correct the permission model if they are available for the affected deployment.
• Monitor for unexpected changes to Steam.exe and related files, and use application integrity controls or EDR to detect local tampering.

Evidence notes

All core facts in this debrief come from the supplied CVE description and the NVD record: weak permissions in the Steam program directory, possible privilege gain via file modification, CVSS 4.8/Medium, CWE-264, and the vulnerable CPE entry ending at SteamOS 3.42.16.13. The supplied NVD metadata also lists third-party references from Packet Storm and Exploit-DB; those are noted only as corroborating references, not as sources for exploit detail.

Official resources