CVE-2021-25294Public exploitNetwork attack vector

Unauthenticated code execution via serialized activity parameter

Published Jan 18, 2021 · Updated Aug 3, 2024

Unsafe deserialization in OpenCATS 0.9.5-3 and earlier allows remote attackers to execute code through a crafted activity request. lib/DataGrid.php passes the parametersactivity:ActivityDataGrid value from index.php?m=activity to PHP unserialize(), enabling a Guzzle __destruct gadget chain. No authentication or user interaction is required; successful exploitation runs attacker-controlled code with the web server process's privileges.

CVSS severity9.8
Critical
EPSS probability10.68%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Unsafe deserialization in OpenCATS 0.9.5-3 and earlier allows remote attackers to execute code through a crafted activity request. lib/DataGrid.php passes the parametersactivity:ActivityDataGrid value from index.php?m=activity to PHP unserialize(), enabling a Guzzle __destruct gadget chain. No authentication or user interaction is required; successful exploitation runs attacker-controlled code with the web server process's privileges.

The record

CVE
CVE-2021-25294
Published
Jan 18, 2021
Updated
Aug 3, 2024
Vendor
Unknown vendor
Product
Unknown product
Classifications
CWE-502, T1190
Attack vector
network
Privileges
unauthenticated

Timeline

How it unfolded

  1. Jan 18, 2021CVE publishedPublication date reported by the CVE source.
  2. Aug 3, 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

10.0NIST NVDAV:N/AC:L/Au:N/C:C/I:C/A:C
9.8NIST NVDCVSS:3.1/AV:N/AC:L/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-502Deserialization of Untrusted Data
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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