CVE-2017-20051Public exploit

Code execution via unsafe DLL search path

Published Jun 16, 2022 · Updated Apr 15, 2025

Uncontrolled DLL search in Inno Setup 5.5.9 allows local users to execute code when a user launches a crafted installer. The installer executable relies on Windows DLL loading without constraining every search location, allowing an attacker-controlled library to load before the intended system library. Exploitation requires local placement of the library and user interaction to start the installer; the loaded code runs with the installer's privileges.

CVSS severity7.8
High
EPSS probability0.57%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Uncontrolled DLL search in Inno Setup 5.5.9 allows local users to execute code when a user launches a crafted installer. The installer executable relies on Windows DLL loading without constraining every search location, allowing an attacker-controlled library to load before the intended system library. Exploitation requires local placement of the library and user interaction to start the installer; the loaded code runs with the installer's privileges.

The record

CVE
CVE-2017-20051
Published
Jun 16, 2022
Updated
Apr 15, 2025
Vendor
Inno Setup
Product
Inno Setup
Classifications
CWE-427, T1574.001
Attack vector
local
Privileges
unauthenticated

Timeline

How it unfolded

  1. Jun 16, 2022CVE publishedPublication date reported by the CVE source.
  2. Apr 15, 2025Record 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=n/a

What conditions does exploitation require?

Attack vectorlocal
Required privilegesunauthenticated

What is affected?

Inno Setup · Inno Setupversion=n/a

Published CVSS scores

7.8NIST NVDCVSS:3.1/AV:L/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H
4.4NIST NVDAV:L/AC:M/Au:N/C:P/I:P/A:P

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 10, 2026Sep 16, 2026
Latest reporting daySep 16, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectorlocal
Privilegesunauthenticated
Known exploitationUnconfirmed
Public exploitPublished

Weakness, pattern, technique

CWE-427Uncontrolled Search Path Element
T1574.001DLL Search Order Hijacking

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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