CVE-2026-39393Public exploitNetwork attack vector

Application takeover via cache-dependent installer re-entry

Published Apr 8, 2026 · Updated Apr 8, 2026

Missing authentication in CI4MS before 0.31.4.0 allows remote attackers to take over the application through the install route. InstallFilter::before() blocks setup only when both .env exists and the volatile settings cache is nonempty, while the installer overwrites .env from unvalidated POST data. Exploitation requires a cache miss while the database is unreachable; the CSRF-exempt route then redirects database traffic to attacker-controlled infrastructure.

CVSS severity8.1
High
EPSS probability0.42%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Missing authentication in CI4MS before 0.31.4.0 allows remote attackers to take over the application through the install route. InstallFilter::before() blocks setup only when both .env exists and the volatile settings cache is nonempty, while the installer overwrites .env from unvalidated POST data. Exploitation requires a cache miss while the database is unreachable; the CSRF-exempt route then redirects database traffic to attacker-controlled infrastructure.

The record

CVE
CVE-2026-39393
Published
Apr 8, 2026
Updated
Apr 8, 2026
Vendor
Ci4MS
Product
CI4MS
Classifications
CWE-306, T1190
Attack vector
network
Privileges
unauthenticated

Timeline

How it unfolded

  1. Apr 8, 2026CVE publishedPublication date reported by the CVE source.
  2. Apr 8, 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=< 0.31.4.0

What conditions does exploitation require?

Attack vectornetwork
Required privilegesunauthenticated

What is affected?

Ci4MS · CI4MSversion=< 0.31.4.0

Published CVSS scores

8.1GitHub, Inc.CVSS:3.1/AV:N/AC:H/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 10, 2026Sep 16, 2026
Latest reporting daySep 16, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectornetwork
Privilegesunauthenticated
Known exploitationUnconfirmed
Public exploitPublished

Weakness, pattern, technique

CWE-306Missing Authentication for Critical Function
T1190Exploit Public-Facing Application

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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