CVE-2025-55739Network attack vector

Authentication bypass via shared OAuth signing key

Published Sep 4, 2025 · Updated Feb 13, 2026

Authentication bypass in FreePBX PBX API affected releases allows remote attackers with the shared OAuth key to forge JWTs for API access. The module packages one identical OAuth private key across RPM and DEB installations instead of generating a per-system signing key, so JWT signatures from one instance validate on another. Exposure requires the API module to be enabled, configured, and activated for remote inbound connections; a forged full-scope token permits reading and changing data through the REST and GraphQL APIs.

CVSS severity8.6
High
EPSS probability0.41%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Authentication bypass in FreePBX PBX API affected releases allows remote attackers with the shared OAuth key to forge JWTs for API access. The module packages one identical OAuth private key across RPM and DEB installations instead of generating a per-system signing key, so JWT signatures from one instance validate on another. Exposure requires the API module to be enabled, configured, and activated for remote inbound connections; a forged full-scope token permits reading and changing data through the REST and GraphQL APIs.

The record

CVE
CVE-2025-55739
Published
Sep 4, 2025
Updated
Feb 13, 2026
Vendor
FreePBX
Product
PBX API
Classifications
CWE-522, CWE-798, T1550.001
Attack vector
network
Privileges
authenticated

Timeline

How it unfolded

  1. Sep 4, 2025CVE publishedPublication date reported by the CVE source.
  2. Feb 13, 2026Record 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=< 15.0.13
  2. Affected versionversion=>= 16.0.2, < 16.0.15
  3. Affected versionversion=>= 17.0.1, < 17.0.3

What conditions does exploitation require?

Attack vectornetwork
Required privilegesauthenticated

What is affected?

FreePBX · PBX APIversion=< 15.0.13; version=>= 16.0.2, < 16.0.15; version=>= 17.0.1, < 17.0.3

Published CVSS scores

8.6GitHub Security AdvisoryCVSS:4.0/AV:N/AC:L/AT:N/PR:L/UI:P/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N
5.1CVE Program CNA recordCVSS:4.0/AV:N/AC:L/AT:N/PR:L/UI:P/VC:L/VI:L/VA:L/SC:L/SI:L/SA:L

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 10, 2026Sep 16, 2026
Latest reporting daySep 16, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectornetwork
Privilegesauthenticated
Known exploitationUnconfirmed
Public exploitUnconfirmed

Weakness, pattern, technique

CWE-522Insufficiently Protected Credentials
CWE-798Use of Hard-coded Credentials
T1550.001Use Alternate Authentication Material: Application Access Token

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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