CVE-2021-45461Known exploitationNetwork attack vector

Unauthenticated code execution via passed URL variable

Published Dec 22, 2021 · Updated Aug 4, 2024

Remote code execution in FreePBX and PBXact with restapps 15.0.19.87, 15.0.19.88, 16.0.18.40, or 16.0.18.41 allows remote attackers to run code. The Rest Phone Apps module passes a URL variable into an execution path, but Sangoma has not published the exact file, function, or validation failure. The affected module must be installed and its HTTP or HTTPS interface reachable; successful exploitation grants unauthenticated command execution and was observed in active attacks.

CVSS severity9.8
Critical
EPSS probability21.66%
Next 30 days · Sep 16, 2026
Known exploitationReported
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Remote code execution in FreePBX and PBXact with restapps 15.0.19.87, 15.0.19.88, 16.0.18.40, or 16.0.18.41 allows remote attackers to run code. The Rest Phone Apps module passes a URL variable into an execution path, but Sangoma has not published the exact file, function, or validation failure. The affected module must be installed and its HTTP or HTTPS interface reachable; successful exploitation grants unauthenticated command execution and was observed in active attacks.

The record

CVE
CVE-2021-45461
Published
Dec 22, 2021
Updated
Aug 4, 2024
Vendor
Unknown vendor
Product
Unknown product
Classifications
T1190
Attack vector
network
Privileges
unauthenticated

Timeline

How it unfolded

  1. Dec 21, 2021Exploitation reportedMalicious activity against FreePBX 15
  2. Dec 22, 2021CVE publishedPublication date reported by the CVE source.
  3. 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

9.8NVDCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
7.5NVDAV:N/AC:L/Au:N/C:P/I:P/A:P
9.4SangomaCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H/E:H/RL:O/RC:C

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 exploitationReported
Public exploitUnconfirmed

Weakness, pattern, technique

T1190Exploit Public-Facing Application

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.

Reported exploitation

Technologies

Your stack

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Your stack

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