CVE-2021-36766Public exploitNetwork attack vector

Authenticated code execution via PHAR object injection

Published Jul 27, 2021 · Updated Aug 4, 2024

PHP object injection in Concrete5 8.5.5 and earlier allows remote authenticated users to execute arbitrary PHP code via logging settings. The Logging::update_logging() method passes the unsanitized logFile request value to file_exists(), allowing a phar:// URI to deserialize attacker-controlled PHP objects. Administrator access is required, and execution depends on a usable object gadget chain in the application scope.

CVSS severity7.2
High
EPSS probability3.68%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

PHP object injection in Concrete5 8.5.5 and earlier allows remote authenticated users to execute arbitrary PHP code via logging settings. The Logging::update_logging() method passes the unsanitized logFile request value to file_exists(), allowing a phar:// URI to deserialize attacker-controlled PHP objects. Administrator access is required, and execution depends on a usable object gadget chain in the application scope.

The record

CVE
CVE-2021-36766
Published
Jul 27, 2021
Updated
Aug 4, 2024
Vendor
Unknown vendor
Product
Unknown product
Classifications
CWE-502, T1068
Attack vector
network
Privileges
admin

Timeline

How it unfolded

  1. Jul 27, 2021CVE publishedPublication date reported by the CVE source.
  2. Aug 4, 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?

Affected buildAffected product and version details are unavailable.

What conditions does exploitation require?

Attack vectornetwork
Required privilegesadmin

What is affected?

Affected products and versions are unavailable in this record.

Published CVSS scores

6.5NIST NVDAV:N/AC:L/Au:S/C:P/I:P/A:P
7.2NIST NVDCVSS:3.1/AV:N/AC:L/PR:H/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
Privilegesadmin
Known exploitationUnconfirmed
Public exploitPublished

Weakness, pattern, technique

CWE-502Deserialization of Untrusted Data
T1068Exploitation for Privilege Escalation

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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