CVE-2016-20039Public exploit

Local code execution via oversized gamma argument

Published Mar 28, 2026 · Updated Mar 28, 2026

Stack-based buffer overflow in gamma argument handling in MAMEdev MESS 0.154-3.1 allows local users to crash it or execute arbitrary code. The gamma option handler accepts an oversized command-line value and writes beyond its stack buffer until controlled bytes replace the instruction pointer. Exploitation requires the ability to launch the local emulator with a crafted argument; successful control-flow hijacking runs code with the invoking user's privileges, while an unsuccessful attempt crashes the process.

CVSS severity8.6
High
EPSS probability0.15%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Stack-based buffer overflow in gamma argument handling in MAMEdev MESS 0.154-3.1 allows local users to crash it or execute arbitrary code. The gamma option handler accepts an oversized command-line value and writes beyond its stack buffer until controlled bytes replace the instruction pointer. Exploitation requires the ability to launch the local emulator with a crafted argument; successful control-flow hijacking runs code with the invoking user's privileges, while an unsuccessful attempt crashes the process.

The record

CVE
CVE-2016-20039
Published
Mar 28, 2026
Updated
Mar 28, 2026
Vendor
MAMEdev
Product
MESS
Classifications
CWE-787, T1203
Attack vector
local
Privileges
unauthenticated

Timeline

How it unfolded

  1. Mar 28, 2026CVE publishedPublication date reported by the CVE source.
  2. Mar 28, 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?

Compare these published version ranges with your installed build and any vendor patches.

  1. Affected versionversion=0.154-3.1

What conditions does exploitation require?

Attack vectorlocal
Required privilegesunauthenticated

What is affected?

MAMEdev · MESSversion=0.154-3.1

Published CVSS scores

8.6VulnCheckCVSS:4.0/AV:L/AC:L/AT:N/PR:N/UI:N/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N
8.4VulnCheckCVSS:3.1/AV:L/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H

CVSS describes severity. EPSS estimates exploitation probability.

Attacks

What attackers are doing with it

Daily unique IPs observed by Shadowserver honeypots for known exploited vulnerabilities (KEVs). Missing observations do not establish an absence of attacks.

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No observations available

Sep 9, 2026Sep 15, 2026
Latest reporting daySep 15, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectorlocal
Privilegesunauthenticated
Known exploitationUnconfirmed
Public exploitPublished

Weakness, pattern, technique

CWE-787Out-of-bounds Write
T1203Exploitation for Client Execution

Public exploit references

Labels summarize the accepted research assessment. They do not indicate a test against your environment.

Technologies

Your stack

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Your stack

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