CVE-2022-4120Public exploitNetwork attack vector

Unauthenticated object injection via CAPTCHA parameter deserialization

Published Dec 26, 2022 · Updated Apr 14, 2025

PHP object injection in Stop Spammers before 2022.6 allows remote attackers to inject objects through second-challenge CAPTCHA requests. The second-challenge handler base64-decodes the attacker-controlled kp parameter and passes the result to PHP unserialize(). The CAPTCHA second challenge must be enabled, and code execution, file deletion, or data disclosure additionally requires a suitable gadget chain from another installed plugin or theme.

CVSS severity9.8
Critical
EPSS probability18.12%
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 Stop Spammers before 2022.6 allows remote attackers to inject objects through second-challenge CAPTCHA requests. The second-challenge handler base64-decodes the attacker-controlled kp parameter and passes the result to PHP unserialize(). The CAPTCHA second challenge must be enabled, and code execution, file deletion, or data disclosure additionally requires a suitable gadget chain from another installed plugin or theme.

The record

CVE
CVE-2022-4120
Published
Dec 26, 2022
Updated
Apr 14, 2025
Vendor
Trumani
Product
Stop Spammers
Classifications
CWE-502, T1190
Attack vector
network
Privileges
unauthenticated

Timeline

How it unfolded

  1. Dec 26, 2022CVE publishedPublication date reported by the CVE source.
  2. Apr 14, 2025Record 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 <2022.6

What conditions does exploitation require?

Attack vectornetwork
Required privilegesunauthenticated

What is affected?

Trumani · Stop Spammersversion=0 <2022.6

Published CVSS scores

9.8CISA-ADPCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
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.

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 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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