Remote code execution via oversized lobby kick count
Published Aug 24, 2026 · Updated Aug 24, 2026
Heap-based buffer overflow in Metal Gear Online 3 1.1.2.8 allows remote attackers to execute code through crafted Steam lobby metadata. The kicked-player parser trusts kick_num as the loop bound and writes attacker-supplied player identifiers past a 16-entry heap buffer into adjacent Steam callback handlers. A match host can trigger the overwrite when a client joins the lobby, corrupting callback function pointers and redirecting execution in the game process.
Summary
What happened
Heap-based buffer overflow in Metal Gear Online 3 1.1.2.8 allows remote attackers to execute code through crafted Steam lobby metadata. The kicked-player parser trusts kick_num as the loop bound and writes attacker-supplied player identifiers past a 16-entry heap buffer into adjacent Steam callback handlers. A match host can trigger the overwrite when a client joins the lobby, corrupting callback function pointers and redirecting execution in the game process.
The record
- CVE
- CVE-2026-19874
- Published
- Aug 24, 2026
- Updated
- Aug 24, 2026
- Vendor
- Konami Digital Entertainment Co., Ltd.
- Product
- Metal Gear Online 3
- Classifications
- CWE-122, T1203
- Attack vector
- network
- Privileges
- authenticated
Timeline
How it unfolded
- Aug 24, 2026CVE publishedPublication date reported by the CVE source.
- Aug 24, 2026Record updatedLatest update available in the CVE record.
Exploitability
Present is not the same as exploitable
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Is a vulnerable build present?
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- Affected versionversion=1.1.2.8
What conditions does exploitation require?
What is affected?
Published CVSS scores
CVSS describes severity. EPSS estimates exploitation probability.
Attacks
What attackers are doing with it
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Public exploit references
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Technologies
Your stack
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Your stack
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