CVE-2021-4283Network attack vector

Stored script execution via unencoded setting values

Published Dec 27, 2022 · Updated Aug 3, 2024

Stored XSS in FreePBX Voicemail before 14.0.6.25 allows remote authenticated users to run script in an administrator's browser. The Settings Handler's views/ssettings.php template inserts saved number and text setting values into HTML value attributes without encoding. An administrator-level user must save a crafted value and another user must load the affected settings view, enabling script execution in that viewer's session.

CVSS severity2.4
Low
EPSS probability0.51%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Stored XSS in FreePBX Voicemail before 14.0.6.25 allows remote authenticated users to run script in an administrator's browser. The Settings Handler's views/ssettings.php template inserts saved number and text setting values into HTML value attributes without encoding. An administrator-level user must save a crafted value and another user must load the affected settings view, enabling script execution in that viewer's session.

The record

CVE
CVE-2021-4283
Published
Dec 27, 2022
Updated
Aug 3, 2024
Vendor
FreePBX
Product
FreePBX Voicemail
Classifications
CWE-79, T1203
Attack vector
network
Privileges
admin

Timeline

How it unfolded

  1. Dec 27, 2022CVE 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?

Compare these published version ranges with your installed build and any vendor patches.

  1. Affected versionversion=n/a

What conditions does exploitation require?

Attack vectornetwork
Required privilegesadmin

What is affected?

FreePBX · FreePBX Voicemailversion=n/a

Published CVSS scores

2.4VulDBCVSS:3.1/AV:N/AC:L/PR:H/UI:R/S:U/C:N/I:L/A:N
5.4NIST NVDCVSS:3.1/AV:N/AC:L/PR:L/UI:R/S:C/C:L/I:L/A:N

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
Privilegesadmin
Known exploitationUnconfirmed
Public exploitUnconfirmed

Weakness, pattern, technique

CWE-79Improper Neutralization of Input During Web Page Generation ('Cross-site Scripting')
T1203Exploitation for Client Execution

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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