CVE-2024-27456

Code tampering via world-writable Ruby source files

Published Feb 26, 2024 · Updated Aug 2, 2024

Incorrect file permissions in rack-cors 2.0.1 allow local users to alter Ruby middleware code through world-writable source files. The gem packages files under lib/rack/cors with mode 0666, so any local account with filesystem access can rewrite code loaded by a Rack application. Exploitation requires shared host access and enables source disclosure, middleware modification, or execution of altered code when the application loads it.

CVSS severity9.1
Critical
EPSS probability0.77%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Incorrect file permissions in rack-cors 2.0.1 allow local users to alter Ruby middleware code through world-writable source files. The gem packages files under lib/rack/cors with mode 0666, so any local account with filesystem access can rewrite code loaded by a Rack application. Exploitation requires shared host access and enables source disclosure, middleware modification, or execution of altered code when the application loads it.

The record

CVE
CVE-2024-27456
Published
Feb 26, 2024
Updated
Aug 2, 2024
Vendor
Rack CORS Project
Product
rack-cors
Classifications
CWE-200, T1574.010
Attack vector
local
Privileges
authenticated

Timeline

How it unfolded

  1. Feb 26, 2024CVE publishedPublication date reported by the CVE source.
  2. Aug 2, 2024Record 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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  1. Affected versionversion=2.0.1

What conditions does exploitation require?

Attack vectorlocal
Required privilegesauthenticated

What is affected?

Rack CORS Project · rack-corsversion=2.0.1

Published CVSS scores

9.1CISA-ADPCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:N

CVSS describes severity. EPSS estimates exploitation probability.

Attacks

What attackers are doing with it

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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
Privilegesauthenticated
Known exploitationUnconfirmed
Public exploitUnconfirmed

Weakness, pattern, technique

CWE-200Exposure of Sensitive Information to an Unauthorized Actor
T1574.010Services File Permissions Weakness

Public exploit references

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Technologies

Your stack

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Your stack

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