CVE-2021-40102Network attack vector

Arbitrary file deletion via PHAR deserialization

Published Sep 24, 2021 · Updated Aug 4, 2024

PHAR deserialization in Concrete CMS 8.5.5 and earlier allows remote attackers to delete arbitrary files through a crafted path. The affected path check passes attacker-controlled phar:// input to is_dir, which deserializes PHAR metadata and invokes an object's __wakeup method. No authentication or user interaction is required, and deletion can compromise site integrity or interrupt service when application files are targeted.

CVSS severity9.1
Critical
EPSS probability1.35%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

PHAR deserialization in Concrete CMS 8.5.5 and earlier allows remote attackers to delete arbitrary files through a crafted path. The affected path check passes attacker-controlled phar:// input to is_dir, which deserializes PHAR metadata and invokes an object's __wakeup method. No authentication or user interaction is required, and deletion can compromise site integrity or interrupt service when application files are targeted.

The record

CVE
CVE-2021-40102
Published
Sep 24, 2021
Updated
Aug 4, 2024
Vendor
Unknown vendor
Product
Unknown product
Classifications
CWE-502, T1485
Attack vector
network
Privileges
unauthenticated

Timeline

How it unfolded

  1. Sep 24, 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 privilegesunauthenticated

What is affected?

Affected products and versions are unavailable in this record.

Published CVSS scores

6.4NIST NVDAV:N/AC:L/Au:N/C:N/I:P/A:P
9.1NIST NVDCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/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.

Daily unique IPsNo honeypot observations are available for this CVE in the selected window.

No observations available

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

Weakness, pattern, technique

CWE-502Deserialization of Untrusted Data
T1485Data Destruction

Public exploit references

No public exploit references are available in this record.

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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